Ponds, Streams, Waterfalls & Fountains:
eBook on Amazon
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples
eBook on Amazon
by Robert (Bob) Fenner
Protecting liner in a pond from hoofs and claws
Included below is our e-mail, in which you provided very useful advise
<advice>. Thanks! I am still planning, and have more
questions if you would please advise. I have by now seen a raccoon
getting into the pond from under the thorny miniature holly putting his
clawed paws on the nearly vertical pond wall as he slithered to the
bottom (and puncturing it on the rim of the pond when pulling himself
out at the opposite end). So I will have to cover all the liner
with concrete, preferably waterproof.
1. Making the concrete waterproof; I read that mixing equal amount
of Quikrete and Thinset is a good idea? Is it? Do you have
another, better suggestion?
<Mmm, am a fan of using welded mesh (cleaner the better; fave is stucco
wire, but chicken wire will do... tied to... Please do just read here:
and the linked files above>
2. How to keep concrete from sliding down from the walls when
<As the above citation... working it into the wire mesh, perhaps adding
a bit more alkalinity...>
Would 3/8" to 1/2" hardware cloth solve the problem? Do I lay it
over or under the chicken wire?
<Ah yes... the smaller mesh over the larger>
3. Sequence of applying the concrete: Do I put concrete on
the bottom first, let it set a bit--how long, to what firmness--and then
build up the sides--waiting long enough to be able to crawl over the
bottom on boards without ruining it but not too long so the old and new
concrete will bond. (I would wet the side of the setting concrete
to help the bonding.)
<Get help; concrete overshoes... olde clothes; start early in the day...
TAKE YOUR TIME... This is VERY HARD WORK. The concrete can be applied w/
pressurized air (shotcreted) or hand applied by pushing it up the
sides... in a systematic fashion>
Since there are bushes around most of the pond (some very thorny) I cannot
kneel outside of the pond and put concrete on the walls. Can I put a
board on the partially set concrete on the bottom, kneel on it and work
on the sides?
Will the seam safely bond if the concrete on the bottom is only
<Not really; and not really necessary that it does. Best to avoid (cold
joints) though just the same>
4. The water at the bottom of the waterfall will be about 16"
deep. Would it eventually erode the concrete?
<Not for many, MANY years. Decades to centuries>
Should I put a large stone on the bottom where the water will hit the
<If you'd like>
Many thanks for your answers. Best regards, Zuzana Dillon
<And you for your sensible questions. Again, do get help... do on a cool
day; start in the AM... Have friends who have done concrete work assist.
Concrete Pillars 8/3/13
Hello, doing pond expansion (30 x 30 x 3' deep) and need to put short
dock type platform out to put lights on to shine on falls
coming into. Was thinking of 2 concrete pillars set on liner bottom
poured in place with sono tubes 12 inches in diameter. Would this amount
of concrete mess with ph levels? Thanks Bob
<Can; yes... I'd make at least the part that will be underwater w/
plastic cement rather than Portland... give it a spritz of ten parts
diluted Muriatic (then 0.3 M HCl) to leach out most carbonate exposed,
and consider even coating it with your fave foundation prep., plus
colour. I'd also first cast some footings for these pillars (2 X 4's or
sixes will be fine... in a box type arrangement), with some small rebar
upright to tie all together. Do send along progress pix please. Bob
Re: Concrete Pillars 8/4/13
Thanks for info. How big should I make the footing?
<Mmm, something like two by two feet>
Also should I put Like a rock mat or something like that under the
footing since it is being done on top of the epdm liner to help cushion
<Oh! Yes; for sure... a couple of pieces of carpet (remnants) are highly
recommended. I had assumed this basin had or was intended to have a
reinforcing mesh/shotcrete barrier. Do read here:
and the linked files above>
Most all of the pillar will be in water.
<Ah yes; BobF>
Re: Concrete Pillars 8/6/13
Hi Bob, well I can say our Home Depot, Lowes and 3 other lumber building
stores do not have plastic cement. So I figured I would Contact Quikrete
direct, so I sent off email,11/2 days later still no response. So went
back to web site and got phone number for Quikrete northwest
them that I had questions on amount of gravel to add for pouring my 2
pillars and also how many bags it would take to do the job since this is
going to be a special order IF they even have it in the Seattle area
warehouse, the guy on the phone goes ooh,your going to have to talk to
our specialists,I'll transfer you, guess what voice mail, gave him 2
hours called back same thing all day. So I hate to bother you
again but is the product I need a 2121 plastic cement by Quikrete?
It/this will do; but mixed with more than sharp/Silica sand... I would
use 3/8" nominal crushed rock... You can just use a low - alkali/ne
concrete mix of any available type. Bob Fenner>
Protecting flexible liner from (deer) hoofs and claws
First of all, thank you very much for your very informative site.
Could you, please, confirm that the process outlined below would be the
right "recipes" for protecting the liner in a 8' diameter pond from
hoofs and claws, and answer my questions?
Sixty percent of the pond's perimeter are surrounded by thick bushes and
have steep sides with a shelf for plants or large rocks to-be-partially
submerged--unlikely that sharp-footed critters would get in the pond
40 percent have a fast sloping "beach" bordered by a lawn where they are
likely try to enter.
I am thinking about covering the beach and the pond bottom in the
shallow part of the pond with chicken/stucco wire (laid directly on the
liner) and about 1" of Quikrete post mix (suggestion from your web site)
and thickly press into the Quikrete round pebbles and mid-size round
stones. The remaining stones will be scattered over those
imbedded. Should I lay something on the liner before putting down
the wire in order not to puncture it?
<No; no need to lay something over the wire. DO take care to not
introduce sharp (ends) of the wire into the pond itself. IF thus a small
area is to be wire/concreted, use both ends of the roll of wire (that
are terminated, not sharp wire-ended) to end in the pond itself... with
the cut wire-exposed parts out of the pond... in the walk area OR
attached to re-bar as we show in various articles on liner ponds on
WWM's Pond subweb>
And if so, what? Given that stones will be in the Quikrete, is 1'
<Likely so... IF the liner is set on/over original grade (so it doesn't
flex, allow the concrete to crack though it's only an inch thick or so)>
(I am trying to save my back as much as I can!)
<I do understand; and agree>
Does the job have to be done all at the same time before the previous
Quikrete patch fully sets?
<Mmm, yes; all contiguous/connected concrete must be done at the same
I would prefer mixing the Quikrete in a 20 gal pail,
<Mmm, no; either use a wheel barrow or purposeful concrete mixing "tub"
(see the Net re or a large hardware store), AND a short handle flat end
shovel (am not a fan of "concrete mixing hoes")>
start in the middle of the pool and work in batches in the direction
toward the beach and spread the work over 2 or 3 days.
<Must be done on one day... get some help. Much more fun... and do color
the concrete. See the hardware store folks re this as well>
Since there is a liner under the Quikrete the seems between the batches do
not have to be watertight. Did I miss something?
<Will be MUCH stronger done as one piece... one day>
Do you have any other advice? Thank you very much in advance for
your answer. Zuzana
<Keep gathering information, tools, materials... Is there a "pond" or
"Koi, goldfish" society in your area? I'd contact them re helping here.
Do take your time in planning. Bob Fenner>
Re: Protecting flexible liner from (deer) hoofs and claws
Thank you very much for your quick and informative answer.
<Am glad to help you. I had a friend whose pond years back was decimated
by a visiting Cougar/Felis concolor, that left huge scratch marks in the
concrete that had been poured over the liner in the ceremonial
entry/exit area of his liner pond.... My solution to him to discount
To put out a large tray of food!>
I will try to get help as you suggested, and I do have an old wheelbarrow
that will be ideal for the job.
<Ah good (I have two!). Much easier on our backs, and a relative breeze
to wheel over to the area to be applied>
Again many thanks and best wishes to you. Zuzana
<And you, BobF>
Re: Protecting flexible liner from (deer) hoofs and claws
Hmm... I did not even consider cougars! Where did your
<Here in San Diego; La Costa... by chance next to Gene Roddenberry of
Star Trek fame... the combo. driveway had a neat model of "Enterprise"
as his/Gene's mailbox>
I live on the northern edge of the Olympic peninsula and we do have
cougars, although not in my yard (yet). Perhaps the cougar could
feast on the deer that wreck havoc in my garden and I would not have to
spend money on fresh meat for the cougar!
<Heeeee! Ah, the/a great circle of life. Cheers, BobF>
Concrete Pond Project
I read most all of the articles you wrote on wetwebmedia.com pertaining
to concrete ponds. After reading what seems like hundreds of articles
on the subject I found yours to be far more helpful than the rest.
<Glad you found it of use>
I plan to build a good sized water feature on my property and want to
go with a liner underneath concrete for reasons you pointed out in your
articles. Most of the people I've talked to try to sell me on just
a liner but it always seems like a flimsy way to do it and I like the
look and rigidity of concrete. In your article 'Building Concrete
& Liner Ponds' you mention 'In our neck of the woods in
Southern California' which is where I live as well.
Do you offer consulting or could you point me to someone you feel is
good at this?
<Mmm... there may be some of these folks still about... Do try here:
Thanks very much,
<Welcome. Bob Fenner>
Attaching a liner 6/4/2011
Hello I am building my first pond. It is made from concrete
blocks. I do not know how to attach the pond liner to it. I have
attached a pic.
Thanks in advance.
<First of all... very carefully. Important that you warm up
the liner, lay it in, fold it ever so evenly so that the corners
are not too "bunched up"... then to overlay into the
cinder block walls and fill the pond... trim the liner inside the
front edge of the blocks and about half way into the side... such
that there is room for the cap stones/pavers/covering material
over the existing blocks traps and holds onto the liner edge.
Understanzee? Bob Fenner>
New pond construction, concrete/alkalinity
issue -- 3/3/10
Hi, I'm currently building my first pond and have been following a
plan I found in a book. I dug the hole 19 ft x 8 ft x 21/2 ft ,
lined the hole with geotextile & butyl. I then made a concrete
collar on the liner all the way round on the planting shelf and built a
three course brick wall on top of that with engineering bricks and
mortar. It was not long after completing this stage that I found out
that lime in the concrete and mortar was poisonous to fish,
<Can be... there are some not-quite-so toxic cements
I bought a fish friendly silicone sealant and sealed around the joint
between the liner and the concrete collar
<Mmm, these rarely work... Okay, never to my experience>
and bought G4 to coat the concrete and bricks, however after 10 days or
so I filled the pond and have water filling up the wrong side of the
bricks and leaching out lime. Of course the water doesn't leak out
to the soil because the liner comes up to the top of the bricks, my
question to you is, will the leaching stop with various drains and
<Mmm, yes... in time... I would do a couple of dilute acid washes
(HCl...) as gone over on WWM... to speed this along>
will the bricks last submersed in water or should I put another liner
over the top of the construction.
<I wouldn't... unless you're in a "big hurry", the
better part of the alkalinity can be dispensed with in weeks to a few
Also I intend to fix rocks to the inside edge of the pond from the
planting shelf up to hide the liner and at one end have a waterfall
trickling down over the rocks. These were going to be mortared to the
brick work, now I'm worried about lime how should I fix these as it
may be difficult to coat mortar with G4 between rocks. Your help and
any suggestions would be greatly appreciated.
<Look for and use "plastic cement" here Steve. Much less
noxious. Oh and do read here:
and the linked files above, and here:
Steady on, Bob Fenner>
Re: New pond construction, concrete, Alk.
Thanks for your reply, very helpful, just a couple of things, I
didn't get an answer to whether the engineering bricks would last
ok constantly submersed under water ?
Though made of a good deal of cement, these are much more chemically
inert than the mortars commonly employed to cement them together.
Shorter answer, these should be fine submersed>
and living in the U.K. I have never heard of plastic cement but I will
Thanks again Bob.
<Mmm, yes... may well be called summat else. I do see some listings
on Google under the search string: "Plastic cement in
Curing a pond. 2/26/10
I have built a brick form pond that has been cement rendered. Sealant
was applied to the walls it was built against and then to the
brickwork, but not to the cement render on the inside of the pond. I
have tried many ways to
reach a suitable ph level . I have filled the pond, cleaned the sides
and base with vinegar solution and have added both vinegar and mild
(30%) hydro chloric acid to the water. I have left it for a week or
more and repeated the process. However, as soon as I drain and change
the water the ph shoots up. The water source is a neutral 7.It is now
over a month.
Any advice please
PS I live in Malaysia
<Hello Anthony... how "high" is your pH now? If below 8.0,
I would not be overly concerned... As you have already used
vinegar/Acetic and HCl acids for washes, I don't think that more
exposure will help much here, and
perhaps may lead to weakening of the cement (Next time less alkaline
material). It is likely prudent/best to just leave the water in the
system, try growing some easy plants (floating or emersed) for a few
months, and you'll likely see a gradual lowering of pH here. Bob
Re: Curing a pond. 3/8/10
Many thanks for your reply. The ph level was off the scale. I have now
decided to tile the pond and it is now looking better. The ph is about
8 now after 3 days with water and running the filter.
<This may be acceptable. What life do you intend to keep
Once again thanks for taking the time to reply to a stranger and if you
are ever in Malaysia I would be glad to buy you dinner.
<I have been to, and am revisiting your country this summer
(Kuching... in Borneo, then out to Mabul for diving...). You may see me
yet! Cheers, Bob Fenner>
Re: Curing a pond. 3/9/10
I used to be the head of museums in Sabah.
<Ahh! I have likely experienced your work... in Kota.>
I built the largest and the best new purpose built museum in Asia. I
know Mabul and of course Sipadan.
<And Kapalai, and many of the surrounding isles and mainland likely.
I was at these island in the 70s.
<Wow! As you are very likely aware, Sipadan is "closed
down"... to folks staying on it... though the military does more
than live there; and many divers from M and K visit there to dive daily
Also spent a lot of time in the jungles and longhouses.
Met and worked with David Attenborough on numerous occasions and also
We now live in Kuala Lumpur and I run a game fishing business See
www.hook-line-sinker.net or www.angling-malaysia.com
<Thank you for sharing. One/I always wonder whom the folks are
who've done the sort of work you describe. Cheers, Bob
Plastic Concrete over PVC Liner --
I have a book on water garden design that has a brief section on using
Plastic Concrete layer over the PVC liner. I am considering this for a
new pond I am installing myself. I read your article about this as
have a few questions:
The book recommends a 1 inch layer of plastic concrete with chicken
wire mesh. Your article recommends 3-4 inches thick plastic concrete.
If the concrete is for UV Protection, puncture protection, and
aesthetics it would seem that 1 inch would be sufficient as cracks in
the concrete would not result in leaks if the cracked pieces stay in
<Mmm, not really.. the concrete fulfills a few functions... one
other is prevent puncture... a one inch shell will very likely crack...
with time, folks walking on it, freezing weather...>
Note, I live in Maryland (no earth quakes to worry about) but my soil
is sandy so could shift/settle.
I plan to do it myself (with a friend or 2) if it only needs to be
1" thick (need a little more than a yard), but at 4" that
would exceed my capability to handle the materials (would have to
call-in the cement truck and don't
know if Plastic Cement is available by truck in my area, it is not
carried locally in the mega home improvement stores).
<Odd that it is unavailable... Is at all Lowe's, Home
Depot's I've ever been to... Another poss. is for you to rent a
small concrete mixer, and with a few friends, mix and place the
Next question is when researching Plastic Cement by Quikrete, their
spec sheet refers to an alternative material called Fiber Reinforced
Stucco which is available sanded. Are you familiar with this
<Yes... is like their concrete mix, sans the aggregate>
Any issues, like alkalinity issues?
<Is much more alkaline than Plastic cement products... wear gloves
if you have a sensitivity>
It might be able to be used thinner with few cracks.
<Mmm, again... not really>
Third, the book recommended 'chicken wire' in the 1"
concrete. Your article
goes a little farther and specifies 3/4 inch "chicken wire",
but I am
guessing that 3/4" is the mesh density not the wire diameter.
<Correct, the specification is the "gap" size twixt the
Chicken wire in my area is not something I find as a specific
<Can be called "wire mesh"... again, is at all HD's,
more like a type of fencing material so I need some more specifics to
see what is recommended. I am very concerned that I will puncture the
liner when installing the heavy-duty wire mesh and concrete resulting
in a leak that at that point would be very difficult to fix with liner
under concrete. Is this a realistic concern?
<Can be... You just need to be careful when laying in the wire...
the layers (comes in determinate heights) can be tied together (best
with "hog rings") to prevent loose, spiky ends from flaling
What wire diameter do you recommend for my do-it-yourself residential
1400 gallon pond?
<Either 3/4 or 1"... You can maybe sub "stucco wire"
(sans the cloth) if other steel wire is unavailable>
It seems to me a plastic lawn/garden netting would be a lot easier to
manage with less risk of puncture. Is this a reasonable substitute?
<No... the concrete won't "form" crystals about,
making the shell, structure that much weaker.>
<Tammy, do look about... Craig's List, online directories, the
Yellow Pages for folks with experience to lend you insight here. Bob
Plastic Concrete? - 06/05/09
I greatly appreciate the numerous articles and responses to questions
that I have found from you as I have scoured the internet for a variety
of information relating to ponds, pools and water features. I have a
question regarding the use of plastic cement in fish ponds and
I have already completed excavation of a waterfall that leads to a
pond. I've made a few of these in the past, and they all have been
'liner only' streams and ponds. I've decided to have this
water feature utilize an EDPM liner, and then a concrete layer on top
of the liner (first time for me w/ concrete for me). The liner is all
in place, and I have supported chicken wire about 2.5 inches above the
EDPM liner using hundreds of 2.5 inch cut lengths of 2' ABS pipe
(the 2.5' sections are held in place using zip ties that attach the
ABS pipe sections to the wire; single drill hole through the pipe works
fine). I'm ready to start with the concrete (I'll be hand
packing J), but have a few questions.
I had planned on using a Portland cement based concrete (3 parts
aggregate, 2 parts sand, 1 part cement) for this project, but was in
intrigued by a number of references to plastic cement on the internet
and in some newer books on water features. I am pretty sure that I want
to use plastic cement, but I am unsure as to whether I should have an
under-layer of 'traditional' concrete (and then a layer of
plastic cement), or if I should just stick to a structure that utilizes
plastic cement alone.
<Just the plastic cement in place of the Portland>
I plan on an overall thickness of about 3+ inches; is this thickness ok
for plastic cement?
<Yes... along with the aggregate (small sized... "pea"...
nominal 1/4", and sharp sand, water... oh, and color/oxide>
My understanding is that a standard 'mortar' mix for plastic
cement has about 4 parts sand to 1 part plastic cement.
<Yes... but I would add some aggregate... likely at least 1, 2 parts
to the mix here... won't weaken, will improve the looks>
I was thinking about laying some plastic (thick garbage bags) over the
cement as it hardens,
<Mmm... I wouldn't...>
and then placing the larger rocks on top of the plastic to make
indentations that will later accommodate the rocks.
<Well... I would try to just mortar all in place as you go along...
start from the bottom... and do your best to not make too much of a
mess... use large "yellow sponges" and clean water as you
work your way up... Not possible, practical to "pre-make"
spots for the rock later... nor necessary for seal/leaking's sake
due to the use of the EPDM liner>
Once again, I'm kind of thinking that a plastic cement (mortar mix)
might be a good way to then fix the rocks in place (in the indentations
made earlier). I initially thought I would use some sort of latex or
foam sealer to fix the rocks in place, but I'm starting to think
that maybe the plastic cement might do well for that also.
<It will... and is the route I would go... Have some labor/help
there if this is a big job... to mix the mortar/concrete, help with
I also wonder if you can make concrete from plastic cement.
<Yes you can and should>
It seems that Quikrete's plastic cement is just Portland cement
with latex additives,
<Mmm, yes... and this co. does have some cheap to better admixes,
mixtures... but I encourage you instead to "make your own"...
buy the big bags (90#) of plastic cement, and sand, aggregate,
colour... and blend, mix yourself just ahead of applying>
so I thought that maybe using pea gravel aggregate would not only be
esthetically pleasing, but maybe would give some addend strength to the
overall project (I really don't want to have to redo this later on
due to cracking J).
<No worries re in any case>
And if that isn't enough, I've also heard that a mixture of
just plastic cement and water (to a paint-like consistency) makes a
good sealer for concrete work.
Am I getting carried away with the idea of plastic cement?
<Not at all... is much easier to work with, less caustic...
"prettier" as well>
Thanks very much, Dennis
<Certainly welcome. Bob Fenner>
Re: Plastic Concrete? 6/5/2009
Thanks very much for your response and suggestions; you have really
cleared things up for me and I am excited to move forward with the
Once again, thanks - Dennis
<Welcome Dennis... this does read as a well-thought out project...
Am sure you will enjoy the process and product. BobF>
Help, don't understand FAQ response --
Just wanted a little clarification on this Liner and Concrete Pond
"Cementaceous construction inside biological ponds
Robert, Have sandy soil for my pond, have question about using mortar
and flagstone on inside to make walls. Can the mortar be toxic to
<Is to a varying extent, depending on make-up>
I have heard of a plastic cement but can't find any info .
<Use of plastic cement/s is advised. Are less caustic, toxic...
still better to lower level of the basin/s while doing, curing this
work. Bob Fenner>"
When he built my sunken pond, the builder dry-stacked cobbles over the
liner. The walls are quite steep and the cobbles slump. I'm tired
of restacking them every year. I want to cover the liner like Bill
here. I don't understand is Bob's comment, " . . . still
better to lower level of the basin/s while doing, curing this
work." What did Bob mean?
Thanks so much - really appreciate your help.
<Gosh Carole... though I wrote this, I don't "get it"
either... Is there more? I don't find the original you've
copied here in:
Will you please check above and below this clip and see if there is
summat more that will help me put in perspective? But, to respond to
your question, yes to putting in some reinforcing mesh (and mortaring
permanently those cobbles. BobF>
Re: Help, don't understand FAQ response
You are fantastic! Here is the link - item is about half-way down:
<Oooh... I think I " get it" this AM... Am encouraging,
cautioning the writer to lower their water level to prevent contacting
the new mortar (with their permanently placing a flagstone
berm/edging), rather than
leaving the pond basin filled all the way to the top. It will be
necessary for you to drain your pond completely... and hold your
livestock in quarters for a week or more elsewhere. Cheers, Bob
Pond building, liner ap. 7/9/08 Hi hope you
can answer my question I have a sunken garden pond
11'x6'x3' which is home to around 12 fish including 4
showas and 2 19"+ orf's. The thing is i want to build a raised
pond standing on a hard standing patio i have which measures
23'x18'x10", half of which is taken by my decking. The
pond i want to construct a pond 11'x6'x3.5' with a liner,
would this hold on the concrete. thank you <Mmm, better to best to
"finish" the shell... a monolithic cast of concrete? Or
block... and "trap" the well laid in liner in a cap of some
devising... can be formal... or mortared rock of some sort. I would NOT
try to stick/adhere the liner to a structural wall, base... Best to use
liner type, thickness as per:
http://wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm the second
tray... "Liners..." fitting through puts (drains, returns...)
loosely with some liner around them for movement... Bob
Sealing toxic effects of hydraulic cement
10/19/07 Robert, <Dana> I read with zest (and hope) your
articles, FAQs, and related links regarding leaky ponds, but I could
not find a solution to solve my dilemma. You're probably going to
laugh hysterically when you read about my problem but here goes... We
have a very old and small (<500-gal.) above-ground fish pond. Three
large goldfish and one river perch have called it home for years.
It's base construction is river rock, concrete, and a thin coating
of Gunite (leftover from an in-ground swimming pool installation). We
used to run a 3/4 hp pump for circulation but over the last few years
the pond lost so much water daily that we no longer had to aerate the
water. <... for 500 gallons? I'd very seriously look into
more/modern pumping here... Will save you a bundle in electrical
cost> We let a garden hose trickle into the pond to replenish the
water. [Are you smiling yet?] Anyway, we were recently given a large
supply of left-over building materials, including about 80 lbs of
Quikrete Hydraulic Cement. Sooo, you guessed it, we lined the entire
pond with hydraulic cement. Yes, you read correctly, the entire pond
was meticulously hand-lined with concrete plugging material. [Are you
laughing aloud?] It should be waterproof, yes? <Hopefully... if the
basin itself is not "moving", badly cracked...> My dilemma
is this... we want to neutralize any toxic effects of the hydraulic
cement by applying a safe non-toxic top coat or paint. Therefore,
please recommend a suitable Thoro product. Do you think their
waterproofing paint would be safe for the fish and sufficiently block
any toxic effects from the hydraulic cement? Please advise. <Mmm,
their Thoroseal should do it... You can color this if you want... with
an oxide/coloring agent... available most everywhere. Though will be
about what it's going to be in time with algal growth> Many
thanks for your invaluable information. Dana <Welcome. Bob
Concrete pond specification 6/25/07 Dear
Sir, I am about to undertake a pond project.. If I can give you a bit
of background to the situation you could possibly advise if this
project would be viable and assist with the technical specification to
make this possible.. Having recently purchased a building plot we
uncovered a former bomb shelter under what we thought was a mound of
earth.. Now with house complete and ground works underway we are about
to embark on the pond.. What we have done is take the top of the
shelter with all debris pushed inside to create a base. What we have
now is a structure 4.9mts x 2.4mts with an undetermined depth..(4brick
thick at ends 2bricks thick at sides) My thoughts were to form base
with 150mmsub base DPM and 100mm concrete to finish , line internally
with concrete block, render and tank internally.. My uncertainty
surrounds what materials to use with regard to waterproofing/ what size
pump/filtration etc.. finished article would be approx 4.6mts length x
2.0mts wide x 0.75mts deep.. Any advice in this regard would be
gratefully appreciated.. Dave Greenland <Mmm, well... there are a
range of ionic-sold/non-elastic coatings one might use (cement
"plasters" for instance) which are fine for "original
grade", solid foundation applications... for vertical-sided,
formal ponds... Some more elastic (e.g. chlorinated rubber based)
materials... but I do encourage you to consider (moving all the way
ahead to unreliable settings where the base may indeed move) to use a
liner here... Please read:
pieces in the tray under "Construction" re Liner Use. Bob
Chemical impact from Gunite 12/1/06 We are
having a pool built, the plumbing and Gunite are complete and the
decking has been formed. We recently discovered or uncovered the dirt
around the pool plumbing and noticed that Gunite has been mixed in with
the dirt and is resting on and near the PVC pool plumbing. During this
discovery someone told us that Gunite has a chemical that will
eventually get into the PVC plumbing, contaminate the water and
potential erode the PVC pipes. <Mmm... this is news to me... look up
Gunite on the Net... is basically a very dry mortar of sorts... a
concrete without aggregate and just enough water added/entrained to
allow it to be "worked", accelerated to "stick"...
is alkaline but not that corrosive...> Can this be true? I am
concerned for my health and also for the potential damage to our
decking surrounding the pool. <I would not be concerned here... As
long as the Gunite underwater itself is "cement plaster
coated" (to make it smooth and water-proof) there is no need to
worry. Bob Fenner>
Cementaceous construction inside biological ponds
9/7/05 Robert, Have sandy soil for my pond, have question about
using mortar and flagstone on inside to make walls. Can the mortar be
toxic to fish. <Is to a varying extent, depending on make-up> I
have heard of a plastic cement but can't find any info . Bill
Oglesby <Use of plastic cement/s is advised. Are less caustic,
toxic... still better to lower level of the basin/s while doing, curing
this work. Bob Fenner> New pond, owner 8/21/05 Dear
"Crew": <Jarvis> I just finished building a 220 gallon
pond in my back yard, and is wanting to add Koi ASAP, I'm not sure
what to do though. should I add any baking soda or salt? if yes, how
much should I add? <... what for? I would test the water quality, at
least pH, alkalinity and maybe add an inorganic acid to the water, or
"wash" the sides down with a dilution of this... if the
basins are new, cementaceous... alkaline. Please read here: http://www.wetwebmedia.com/PondSubWebIndex/conclnrconstpd.htm
should i but any water testing kits? <Yes, I would. : http://www.wetwebmedia.com/PondSubWebIndex/tstkitspds.htm and
the linked files above... Bob Fenner>> thanks: Jarvis
Pond construction... mainly 6/31/05 Just recently
we added a cement pond to our back yard. And before putting water into
the pond I need to know what measure should be taken to prevent
leakage. <...?> A few question I have is how long should I allow
the cement to cure before cleaning it with a solution? And what type of
solution should I use? Thanks for your help! Diamondmind <The
basin/s shouldn't leak if they've been constructed properly...
some folks seal concrete with a coating that aids in protecting the
material and rendering it less likely to affect water chemistry. Most
installers use an acid wash to reduce alkalinity... some people just
utilize vinegar here, but professionals often dilute Muriatic (3M HCl)
and brush this on, rinse, pump out... These issues are covered on WWM:
You might avoid a good number of future issues by studying now... Bob
Pond Construction Sat, 2 Apr 2005 Greeting, I have
been reading several of your excellent articles on the web. I am
looking for specifications for a pond with a concrete (or Gunite)
topping over a liner. <Specifications? Your installer (I strongly
suggest "going Union" here) will know what these are...
depending on depth, slope... if you're going to "plaster
coat" the Gunite (I would with something)...> I also need an
installer for a client in the Palm Springs (Indian Wells) area of
Southern California. <Mmm, I'd consult the "Yellow
Pages" under "Swimming Pool Construction"... get at
least three bids, talk with whoever they give you references for their
recent work> I would appreciate any direction or references that you
might have. <Unfortunately it's been many years since doing
actual jobs in your area... but there are likely still a few excellent
companies out your way... There are MANY pools and water features out
that way as you no doubt are aware. Bob Fenner> Rick English English
Waterfalls and mortar Bob, I am building a
waterfall for my fish pond and would like to use mortar to set my rocks
onto the liner so the water will go over the rocks instead of under
them. I am concerned about the mortar leaching out into the pond. Is
there anything I can do to the mortar to prevent this? I've tried
the black biofalls foam and found it very difficult to work with.
Thanks, Gail <Yes. Make sure and use "plastic cement" in
your mortar mix... much less alkaline than "plain" Portland
cements... Mortars are just cement, sharp sand, water and possibly a
coloring agent... and easier on your skin in working with it as well.
Pool slide I have just shotcreted my pool and in
ground slide. Do I need to brown coat the unleveled areas and rough
spots before Thorosealing the slide or will Thoroseal fill in all these
voids? <Not unless the current surface is very rough> Will
Thoroseal provide me a smooth sliding surface; <Not enough to likely
suit you> if so, how do I achieve this. Do I trowel it on or use a
paint roller or brush? That you for your response. <Look into smooth
mortar "plaster coating"... can be done by oneself... but if
this job is very big (like a swimming pool), better to have
professional "pool plasterers" trowel it out. Bob
Acid wash acid for ponds Hi I just read your
article on Thoroseal I just used it to reline my Koi pond you mentioned
a light acid wash before introducing live stock What product can i buy
to do that. Thank-you for your time Danny Fitzgerald <Hydrochloric,
as three molar concentrations sold as Muriatic Acid is your best bet
here. Sold in swimming pool supply shops, concrete et al. businesses.
Please read here re doing such acid washes: http://www.wetwebmedia.com/PondSubWebIndex/acidblchpds.htm
and follow carefully the cautionary remarks. Bob Fenner>
building concrete pond??? Robert, <Jim> I am
constructing a pond with the inside dimensions of 6 x 10 by 3 deep. I
am planning 6" wall and floor thickness. It will have a 3"
bottom drain line and a set in concrete wall skimmer, like a pool.
<Do make the "casting" around this skimmer assembly a good
six inches thick all the way around as well> The walls (sides) are
vertical 90Â°. I have a few questions and am hoping your
experience will shed some light on them. <I'll try> 1. I am
using a 6-1/2 bag mix with ipanex admix for waterproofing and will
plaster the inside with black plaster, is a liner still needed.?
<Not needed... but good/worthwhile insurance... especially in areas
where the ground moves (earthquakes, freezing...)> 2. I am tying
rebar and will hang the inside wall forms as one 4 sided piece
(suspended 6" above the floor. <Make this 3" on your
stand-offs... cast in about the middle> Can I pour this all at once,
floor first then walls....or will it try to seek it's own level.
also do I need a vibrator wand for the walls (trapped air).? <Best
to pour all at once... the floor first... how are you forming up the
walls? If they are vertical... are they being molded somehow?> 3. If
the slump is low enough can I just pump the walls starting at the
bottom and building then vertical. or will it all sink without a form.
?? I hope this will work. <Not exactly... even with an absolute
lowest slump the mix will compact, compress> 3. Don't I need a
hydro-static valve in the bottom drain to protect against the pond
raising out of ground when emptied for maintenance.????? <Yes! Or
other provision...> I would love to use Gunite except the job is too
small. <Mmm, not necessarily too small... Have you checked with the
pool sub's in your area? Do take a read through the "Pond
construction methods on our sites before actually initiating
construction. I encourage you to go with an underlying liner, and for
us to chat re the forming of the walls, bottom of the system. If your
design calls for vertical walls, either reconcile yourself to making
them of block or forming them with plywood and snap-offs... Let's
keep chatting if I'm not being clear. Bob Fenner> thanks Jim
Re: building concrete pond??? bob, thanks for the
assist. a ready mix co. quoted $370 for the concrete and $170-$200 for
the pump... <Mmm, about right> check this ! today got 2 replies
from Gunite guys, one at $1,600 and one at $1,900. think I will stick
to working out the pour version. <... the difference isn't as
much as you might think here... the pour option includes having to
hand-pack, move around... even with the pumper, about seven yards of
concrete... at about 2 1/2 tons a yard... yes, about 35,000 pounds of
material... so, you'll need a few friends, for a few hours... the
Gunite folks will probably finish the shooting, leaving you with only
cement plaster coating to do... something (my back's starting to
ache) to think about> I think your right about the liner. I will
sketch my idea of the form for the pour and .PDF it to you early next
week. got a lot of rebar to do this weekend. <Real good... the
progress will be well worth it... and give you a much better idea of
what you're up against. Bob Fenner>
Ponds, Streams, Waterfalls & Fountains:
eBook on Amazon
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples
eBook on Amazon
by Robert (Bob) Fenner