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FAQs on Pond Repair: Water Falls

Related Articles: Pond Repair WorkLiners for Ponds

Related FAQs: Water Feature Repairs 1 Water Feature Repairs 2, Water Feature Repairs 3, More specifically: Leaks/Leaking, Seepage, Earthen Pond Repairs, Electrical Problems, Fountain Repairs, Faux Rock Repairs, Crack Repairs... & Foundation CoatingsLiner Pond Repairs, Liners in Pond Construction


Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

Water feature water basin seeping 6/3/14
Hello Wet Web Media!
<Howsit Tom?>
I have a waterfall feature with a water basin that holds 50 gallons of water or so. It was built 10 years ago or so and works fine, but now the sealer/lining is seeping to where I have to keep refilling the water once or twice a week. In reading your posts, my plan is to buy the Henry 4.75-Gal. 107 Asphalt Emulsion and spread that all over the area where water stands.
Will that work?
<May be... Allow it (the emulsion) to dry a few days... IF this doesn't "do it"; I'd look to pouring a rather liquid colored concrete slurry in the nooks and crannies of the fall "trough". You've read through WWM re waterfall repair I hope/trust. Bob Fenner>
Re: Water feature water basin seeping 6/4/14

Thanks for the quick response. It¹s not the waterfall portion that is the problem. It¹s really a water wall that drips into a manageable basin, almost like a concrete tubŠ and that concrete tub (which has a decomposing thick
garbage bag-like liner)
is the problem. I also saw you mention Thoroseal. Is that better for my needs than the Henry 4.75-Gal. 107 Asphalt Emulsion?
Thanks again!
<Different application... won't likely adhere to PE. BobF>

Waterfall. Help! Common construction error leak    2/23/13
Dear Bob,
We have a beautiful unfinished waterfall that leaks the rocks at the bottom of the falls are so large that we didn't put a liner underneath.
<Should have put over then... all the way into the basin...>
We used a pool stop leak mortar
<Won't work>
 to seal the rocks and the upper liner to the main fall rock. We are in New England and the mortar cracked in no time. Now we have a quote from some contractors to help us finish the falls and they recommend moving the big two fall rocks with a tractor which could take a whole day they are so large. Also it was very hard to position them even with heavy machinery the first time. On the end we would still have three liners. One for the upper falls, one for the lower and one for the pond.
<These need to overlap, be solvented (above water)... together...>
This seems like a very difficult and expensive proposition especially considering I am great with masonry and we don't have the money to do this.
Help! Is there a mortar we could use that would at least last several years?
<None... the "moving" of rock, mortar will cause the latter to crack>
We have seen other mortared waterfalls I the area but not sure how they were built. Thank you!
Liz Coello in Connecticut
<Do read here (again?):
and the linked FAQs files above... I would lay a liner on top of the "waterfall trough" and put wire mesh, mortar over this... with the discharge pipe of the fall dumping water into the liner/trough, and the liner extending (drain the pond down a foot or so to do this) into the basin/pond. Understanzee? Bob Fenner>

Sealing a Waterfall   7/27/10
I have constructed a waterfall out of large boulders of coral rock (please see photo below).
<I see this>
I used Great Stuff Pond and Waterfall Foam Sealant to fill larger gaps between rocks and DAP 100% Silicone
Sealant everywhere else.
<Won't work to water proof this...>
I did not previously think about the porous nature of the coral rock and now realise that I am losing water
through the tiny holes and crevices. I am looking for a sealer that can be 'painted' on and will give a clear, non toxic filler for the gaps and will withstand constant water flow 24/7.
<There is no such product as far as I'm aware... people have written to me for years re, I built water features for a few decades... there are clear sealants... even ones advertised for this sort of purpose. They have never worked... If you'd care to read a bit re:
I have spoken to DryLok and they do not recommend their product under constant water flow. I discovered SOMAY PST out of Miami but their great sounding project only comes in black! I am at my wits end. Can you help?
Thanks in anticipation.
<I'd rebuild the fall structure with a liner under it, draining back into the pond, as detailed here:
and the linked FAQs file above. Bob Fenner> 


Re: Sea shells in Koi Pond... leak   5/18/10
Not so fast, there, guy... pond NOT REPAIRED yet!!! A borrowed pump is in upper small pond in lieu of installed pump being on to "see if there is a leak in the big pond".
<Barbi... have the "repair people" pressure test the plumbing/lines... easy to do... And add dyes to the basins and test the "water outside" for at least the general source of water loss...>
I know there is not!!!!!!!! It lies either in the waterfall he rebuilt last week...
<Mmm, these can be real sources of trouble... Have you read my olde piece on WWM re waterfall construction? Really need a continuous liner... laid in over a "structural trough">
or the lip flowing into the pond which he really shorted... or the huge, sewer-like pipe from skimmer to bottom of falls box. Yikes......can't stand it!!! You're a good listener, Bob... it's raining... and I just did my windows yesterday. I just love doing futile things!!!!!!! Ugh......yuk......and a few other disgusting remarks not recommended saying on the internet!!!!!!! Barbi
<Steady on Barb... BobF>
Re: Sea shells in Koi Pond, fall repair, reading...  5/19/10

Hey, Bob... will pass on your suggestions to my pond guy... and no, have not read your piece on waterfall construction.
<... Please do: http://wetwebmedia.com/PondSubWebIndex/h2ofallconstr.htm
and the linked files above. B>
I really have my [usually right] gut feeling that my problems lies within the plumbing in the skimmer box to
the falls box or the connection to the falls box. Either/or... dollars being spent and no return other than complete frustration. Not to mention my snow/ice/rain damage in my bay window and insurance adjusters not able to come to assess the damage till Friday. Good thing I don't drink... though perhaps I should start!!!!!! Barbi
Re: Sea shells in Koi Pond 5/20/10

Thanks, Bob... took a break from "give constructive criticism" to my painters... i.e., please don't drip on the carpet... I don't care if it is Latex... there are six drips in this corner... my wall paper didn't have white edges before you started... why does my vintage brass door knob have a white shadow around it... I'm literally ready to tear out my hair!!!!
<Don't do it... step outside yourself... Are you given/partial to the written/printed word? Try "The Book" by Alan Watts... you're a candidate>
Read your short and sweet (like me) article on the falls construction;
<And your writings, musings urged me to spend a few hours ayer splitting up the three Pond Repair FAQs files into more specific sub-categories... including H2O falls>
unfortunately it is too late as it is already done and some of those large boulders are in excess of 1,000 lbs.
<Mmm, actually... a liner can/may be laid in over the area where the water transits, overlaying the pond lip... mortared and more in...>
(Took two men and two pinch bars just to move 'em.) I know... far too large, but that's what was done initially
when I was in my "damn the expense mode". I've since come to my senses!!!!!!!
<What lacking is there in us that our senses don't register the many worlds around us?>
Anyway, thanks for all your help Robert... really appreciate it. Barbi
Will let you know when I am again sane!!!!!!!!!!!
<Ok. B>

Repairing fiberglass waterfall  - 12/04/06 I am trying to repair a prefab fiberglass waterfall. There are no cracks in it. It has lost its original coloring as it is nearly 6 years old. <Yes...> We have about 7 fish and I don't want to use anything that will harm them. Do you know if regular colored grout can be used? <Do know, and no, cannot be used> Thanks for any info you could send my way. <A repair can be made if the original fiberglass/resin isn't too badly delaminated, and the area behind the break is supported well enough (not too flexible)... with fiberglass cloth (look for in determinate widths), color/ing if you'd like, laminating/hot-coat resin and hardener, oh and a "throw-away" small brush to apply it. The falls must be dry, clean, and I'd roughen up the surface with a low grit sandpaper of sorts... do wear gloves, long-sleeve shirt and avoid the bits of fiberglass removed... let cure... Bob Fenner> <<Bob, as I read this letter, I thought he was simply trying to restore coloration to an aged fiberglass structure, not repair a structural piece. I was going to try my hand at a reply, but you beat me to it *grin* My suggestion was to be to dry the waterfall surface and try a buffing compound such as 3M Imperial Rubbing Compound to bring back the coloration... Oftentimes oxidation of this sort is simply buildup on the surface of the fiberglass and will buff right out.. I can't tell you how many lake-worn boats I've brought back to a showroom shine with some buffing compound and some elbow grease. Hope this helps! -JustinN>> >Yikes... do see this as you state (now)... Will re-respond... My input remains the same excepting the use of the fiberglass cloth, tape... roughen up the surface, re-coat with colored laminating (not casting) resin and moderate/measured amount of MEK hardener. Thank you Justin. BobF< >>No problem, Bob, its what I appreciate most about the community here: the group think concept. Ideas are better thought out when you have more eyes looking at problems, I only ask for the same if I have any such similar incidents *grin*, Subsequently, while on the subject of refinishing a fiberglass structure as such, what is your opinion of one-part epoxy paints, such as those used for jet skis? These were some of the more readily accessible, easy to use, and cheap types of paint I dealt with in my time in the body work industry, and always gave very nice results. Would you feel them to be adequate for such a situation as described above? -JustinN<< <Mmm, likely so... given very thorough prep... Part of the reason I like the "hot coat" surfboard/use resins... they're much more "sticky", forgiving. Cheers, BobF>

Lining a concrete pond  11/18/06 Hello WWM Crew, <Brian> Warm greetings from Sydney Australia where we are just entering summer and enjoying the worst drought in a thousand years (I am not sure how they worked that out as records only go back about 150 years!). <And such even numbers... reminds one of "budget" numbers from simple servants in the U.S.> I am very impressed with your extensive knowledge you share with the Web community and thank you for that.  I have a problem I was hoping you could assist with. <Will try> I have converted an old sunken garden into a pond by rendering it and covering the render with a two-part waterproof paint the name of which escapes me.  It is about 10 feet by 8 feet and about 3 feet deep.  It is a very happy home for seven goldfish and a whole bunch of vegetation.  This worked fine for 8 to 10 years but has recently developed a leak.  I found what I thought was the leak, scratched it out and filled with a silicon glue (a Selleys product) which seemed to slow the leak down but didn't stop it. I suspect there are roots from my neighbor's pine trees involved. <Very common> I have decided to line the existing concrete pond with a butyl rubber membrane and although I have scoured your excellent website I can't seem to find an answer to my questions. Can you comment on my decision to line the pond? <Is excellent... the roots will not penetrate this material> How should I attach the liner to the concrete? <Best to fashion a "lip" of sorts to hand the membrane in, pinch it to... and cap this with some sort of masonry with thin set mortar> How should I deal with the flaps produced when folding into the corners of the pond? <Try to "fold them in, leaving a bit loose at the top... though all will stretch and largely lay flat on filling> Thanks in advance, Brian Lee <Welcome my friend down under. Bob Fenner>

Fixing pond leaks   9/5/06 Hi, I have a small outdoor pond that is old and cement.  It has  cracks.   What filler can I use under water and wet that won't kill the  plants or fish?   Geralin <... No filler... need to remove all, repair... Please read here: http://www.wetwebmedia.com/PondSubWebIndex/concrepart.htm and the linked files above. Bob Fenner>

Waterfall repair question Mr. Fenner, <Mike> I read your articles on pond repair and have a question on the "other" materials that can be used to seal a waterfall.  I am in Hawaii so some materials are hard to come by. <I know... we own a house mauka of Kona... and visit there often> Our waterfall has two basins that spill into the swimming pool.  A liner was used but there is a lot of leaching (white stuff, lime?) out of the grout joints between the rocks. <Mmm, you might want to consider trying to effect a repair/change here... acid-washing the area, letting it dry and coating the rock... there are a few materials that can be used here>   The top basin drains down a good 6 inches overnight, mostly into the second basin which drains (or should I say leaks) down an inch or two.  There is also a little area on one side where the waterfall was going to have a side path that was eliminated, and water leaks into that area Looks like it is probably following the liner into that area after it leak through whatever crack or defect there is. <Okay> The waterfall was built using a liner so we aren't losing the water, just leaching/leaking it into the pool.  Over the liner was a base of concrete made from Hawaiian cement (not plastic cement) and a fine crushed rock, the consistency of coarse sand.  Rocks were set on it later.  Then the contractor plastered the basins with a sand, cement, and ad-mix mixture. <Good explanation>   I would like to replaster the basins to try and stop the leaking.  Is it o.k. to use this type of mixture or should I try something else? <If it were mine, I'd likely make a mix of plastic cement, sharp sand, oxide to color to something akin to the rock and the aggregate... and a good dollop of admixture (looks like white glue)... to make it stickier.> Do I need to acid wash before I do this? <Yes, I definitely would... and of course let dry> What is the white stuff leaching through the grouted joints? <Mainly calcium carbonate... with some calcium oxide and silicate> Thanks for you help, Mike <Welcome. Bob Fenner>

Waterfall Sealer Greetings, I have an old (15 yr) waterfall constructed of rock and what looks like regular masonry mortar. When built, I do not believe there is any water barrier substrate that was put behind the stone so the waterfall now leaks like a sieve. I have filled mortar gaps with several different products that reduced the leakage, but I am still losing about 20% of my pond water daily to leakage out of the system. Can you recommend a clear, preferably acrylic, stone/mortar sealer that I can paint of the surface to seal it? I have fish in my pond, so it needs to be non-toxic. Any recommendations? <Unfortunately all the clear sealers I'm aware of have no "body" or elasticity... My only real suggestion is to use the present fall structure as your "structural trough", lay a waterproof liner over this and mortar a new one over it, making sure the water discharges well-over/into the new underlying liner. It seems you're familiar with the "waterfall construction" piece archived on WetWebMedia.com, perhaps this can grant your further insight. Bob Fenner> Thanks for your help. Jon Usher

Waterfall problem Help! The design:                    A little over a year ago we expanded our patio and added a retaining wall using Crab Orchard fieldstone (and other stone) with an integrated waterfall.  The lower concrete pool contains a pump which pumps water to the upper concrete pool which when full, over flows down the face of the stone and collects in the lower pool.  The pools are no more than 4 feet long by 2 feet wide by 2+feet deep. The problem:               We have noticed a loss of water volume during operation but don't notice water leaking from the horizontal (patio) or vertical (either side of the waterfall) surfaces.  Neither pool losses leaks. The suspicion:             Other than minimal amounts lost via evaporation and absorption, water may be leaking through 'imperceptible' mortar joints between the stone. <Very common>   I cannot conceive of another reason for nearly the entire loss (approximately 2 feet/day) of water. The solution:                If my suspicion is correct, then an application of a clear, waterproofing material over the surface of the stone may prevent rapid water loss.  If so, what product is recommended? <Unfortunately as far as I know there are no such clear sealants. I recommend a cementations coating (like Thoroseal tm) that can be dyed to somewhat match the rockwork... note the height of water in your falls during operation and apply this material up to that point. If there is a suspicion that the rockwork is still moving (it was built on a solid foundation I trust), you may be better off with a coating with elastomeric properties (so it can/will stretch rather than crack)> If suspicion and solution are incorrect, please provide additional advice! <Bob Fenner>

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
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