Most of the threads I've read have dealt with specific pond coatings and I thought it would be helpful to try to have a discussion where we can summarize as many of the options as we can. My requirements for the sealing system is that it be maintanance-free for 10+ years, highly reliable, contributes to fish health, and is aesthetically pleasing. Cost and ease of installation are also important factors.
Here are my thoughts on some of the popular options based on what I have read after digging through koiphen and searching the web. Thanks to many people who have shared data in the past. PLEASE add your thoughts, Pros and Cons and if you have photos, please add that as well. I might come back and edit this original post as hopefully others add new information to this thread.
EPDM Sheet Liner:
Cheapest option, but once you add in the cost of shipping, and tape/sealants (if the wrinkles bother you), the cost starts approaching what some of the cheapest coatings might cost. Taping the wrinkles also adds to the labor involved in installation. The wrinkles are an aesthetics issue as well as potential areas where debris can deposit, so for me, taping them is a must. Can be used in a sloped wall dirt foundation, but if building a koi pond with vertical walls, a concrete collar and/or block walls to support some or most of the wall is a must to avoid wall collapse. 20 year lifetime claimed on Goodyear EPDM.
Pricing: HaveytheKoi is the only one I know that has seamed/taped all the wrinkles of an EPDM liner. Maybe he can offer a price estimate including tapes, shipping, etc. per average sq. ft as well as labor involved? I'm guessing under $800 for a typical 20'x12'x6' pond including the expensive tape, sealants, with an allocation on budget for various liner bulkheads for several TPRs etc.
Pros: Can be DIY, low cost, perhaps ease of installation if not taping wrinkles
Cons: Taping wrinkles will add to installation, larger ponds will require several people to install as a large liner will be 400 pounds or more, consideration must be given to avoid punctures when going into pond, or installing things in years to come, requires bulkheads or pipe boots for penetrations.
EPDM thinkness: 45 mil typical and recommended by most
Here is a good thread on this kind of construction:
https://www.koiphen.com/forums/showthread.php?t=12806
Polyurea:
In my opinion, the best option if price is no object. This is not a DIY option and requires hiring a professional due to the equipment needed. I would much prefer to have a concrete or gunnite shell to apply the polyurea on, which increases the price considerably. Curing time for the concrete/gunnite needs to be considered in terms of scheduling. Some applicators spray polyurea onto geotextile fabric or slurries. Geotextile/Polyurea is not a structural support so this has to be a consideration when trying to install vertical walls. I have seen samples of polyurea on geotextile, and I would be comfortable using this option on the FLOOR of the pond assuming the dirt underneath is solid or pretty well packed down, but I would still want a solid wall to support the sides, probably using a solid footer, plus reinforced concrete blocks.
Pricing: ~$10/sq.ft. of sprayed area for polyurea spraying. Cost of rebar, gunnite, etc. will vary with the job. BobinCa graciously posted that his gunnite job cost $5900 for 21+ yards of gunnite. Rebar and plumbing cost an additional $4000. So that is $10k then add in the cost of spraying.
Pros: 700% elongation properties for this tough elastomer makes it durable with high confidence in success assuming knowledgable installer is used. Allows many pond design options as well as flexibility in installing pond penetrations such as TPRs, bottom drains, skimmers etc.
Cons: Expensive, especially if used with a rebar/gunnite shell. Proper installation key or pin-holes can develop requiring patching. Not a DIY option.
Thickness: Depends on applicator, 80 to 120 mil is what I have been told
Good thread to read about Polyurea construction:
https://www.koiphen.com/forums/showthread.php?t=17995
Other useful discussion about Polyurea:
https://www.koiphen.com/forums/showthread.php?t=10976
Sanitred Permaflex and LRB/TAV
An option gaining popularity on Koiphen seems to the Sanitred products, partly I think due to BobinCa who as far as I know is the first to use this product on a "proper" koi pond. Sanitred has many apparent similar pros and cons with polyurea except that it is a product that can be DIY, and provides significant cost savings. Other threads discuss the details of the product, but essentially the Permaflex is a two-part mix that can be painted/rolled onto a firm shell such as concrete, gunnite, or concrete block. The LRB/TAV is mixed with minimum ratio of 2:1 LRB:TAV and provides a thick paste applied via troweling to fill in voids and generally smooth out the shell. Another coating of Permaflex is then applied on top of the LRB/TAV. Highly questionable if this product could be used on flexible geotextile. According to Sanitred, Permaflex literally "bonds" to concrete and other surfaces and is not just a coating adding to integrity of sealing system. Permaflex is suppose to bond well to itself allowing for easy repairs, but my understanding is that if greater than a 24 hr period has ellapsed between coats, the previous layer has to be "prepped" prior to application of new layer. Nature of prepping is unclear (someone add?)
Misc. data: High elongation properties allow adjustment in case small non-structural cracks develop in the underlying shell. AR-Permaflex has 590% elongation properties with 2030 psi tensile strength, LRB/TAV has 650% elongation properities. Product can be cold cured and applied at above freezing temperatures.
Cost: At this time (Sept. 05)
AR-Permaflex is $389/5 gallons which is equivalent to $77.75/gallon (gallon pails cost a bit more). The recommended thickness is 20 mil, but I believe two coatings are needed, with each coating requiring 1 gallon for ~80 sq.ft. So if I understand it correctly, 1 gallon at 2 coats and 20 mil will cover 40 sq. ft. To account for imperfect surfaces, coverage may be lower. Then factor in the cost of LRB and TAV the use of which varies depending on surface texture and voids.
LRB is $324/5 gallons which is equivalent to $64.75/gallon.
TAV is $215/5 gallons which is equivalent to $$43/gallon.
BobinCa shared that his 470 sq.ft pond required $871 (shipped) of product to cover his pond. This works out to $1.85/sq.ft.
Pros: DIY-friendly, cost is cheaper than polyurea, advertised properties from manufacturer indicate it is well suited to provide a long lasting, high quality, and reliable finish for the pond.
Cons: Installation cost is still not cheap as it requires a structural support not just for the vertical walls, but for the floor as well. So it is only considered cheap in relation to polyurea. At this point, longevity in koi pond applications have to be proven - many are confident it is not an issue. Clay reports that his discussions with a farmer indicate the successful long lasting use (12 years?) of this product in a non-pond application.
Thickness: Recommended thickness is 20 mil. I would personally apply it thicker including the LRB/TAV and multiple coatings of Permaflex.
Thread on pond using Sanitred Products:
https://www.koiphen.com/forums/showthread.php?t=18602
Discussion on Sanitred products:
https://www.koiphen.com/forums/showthread.php?t=18157
Gator Guard
My research into Gator Guard has been minimal. I'm not sure what chemistry it has and if it is indeed the same as polyurea under a brand name?? But similar to polyurea, it can not be done DIY and requires a professional installer. Someone else may need to chime in to fill in the blanks, but here is a thread that discusses the construction of a pond using Gator Guard:
https://www.koiphen.com/forums/showth...2&page=2&pp=40
No info at this time on pricing
CIM or CIM 1000
This is a 2 part "liquid qpplied urethane coating" that can be applied on a structural shell like concrete or gunnite. Offers 400% elongation. Approved for potable water, so should be fish safe. Can be used with a special fabric for areas that require extra strength (I do not believe this is intended to mean it can be used on dirt floors and especially not as vertical support).
Cost: $400/5 gallons (corrected) with recommended 60 mil or 1/16 inch thickness, 1 gallon covers 18 sq. ft. so pricing is $4.44/sq.ft. Again, the shell price must be added.
Pros: Similar to advantages of Sanitred
Cons: Similar to disadvantages of Sanitred, more expensive than Sanitred products
Others please chime in on differences between these various products.
Pond Armor's Pond Shield
A DIY 2-part mix epoxy product applied to firm structural support. Producer advertises the products use for sealing wooden construction ponds. Single coat provides the recommended 10 mil. Can be touched up and recoated up to 72 hours without additional prep. Piping requires sanding for improved adhesion. This product can be used with fiberglass, tape, etc. to improve strength (Again, this is not intended for bare dirt application). This thick formulation is suppose to avoid sag on vertical applications. No primer or sealant needed.
Cost: $75/1.5 quart kit provides coverage of 60 sq.ft at 10 mils. This is $1.25/sq.ft. Add in the cost of proper shell.
Koi Kote
Use to be sold by Pond Armor, but appears to have been replaced by Pond Shield.
Bondglass-Voss G4
Popular product used in the UK. Moisture cured Polyurethane uses moisture in the air and substrate to cure. Can be applied down to 0 C temperatures. Must be applied onto cement rendering as porous concrete block is too open and absorbent. Render must not contain water proofing additives. Recommended rendering = 1/2" thick. G4 will not bond to PVC.
Cost: ?
Hecht Rubber:
Requires cleaning of the concrete or gunnite pond with TC-700 product. Then application of P-SC primer. Three coatings of Black or gray H-55 neoprene rubber is then applied by brush. Dry time is quick between coatings of 60 minutes. Cure time is 24 hrs. 72 hrs to introduce fish. Reportedly provides very good bonding.
Cost:
Black H-55 rubber = $110/gallon, 1 gallon covers between 80 to 100 sq. ft.
TC-700 cleaner = $55/gallon
P-SC = $59/gallon
Making a guess at the usage of primer and cleaner at 1/3 as much as the rubber, I'll estimate a cost of $1.65/sq.ft.
Pros: advertised qualities sound great.
Cons: reports on Koiphen indicate quite a few users have experienced pealing of the coating after a year or two of use. Undetermined if proper application procedures were used. Another user reported no problems after several years.
Here is a recent thread on Hecht:
https://www.koiphen.com/forums/showthread.php?t=24716
Liquid-Roof.com
EPDM and curing catalyst. Web-site indicates non-immersion application. Cannot be applied to porous blocks, must use primer. Elongation at 180 to 200%, with tensile strength at 680 psi.
Cost: $372 (shipped)/5 gallons, at ~200 sq.ft. coverage, at 20 mils thick, equates to $1.86/sq.ft.
Whew... that's about all I can contribute at this point. I hope this is helpful to others in my situation trying to decide what type of sealing system they want to use on their pond. EVERYONE, please chime in with your opinions, experiences, and recommendations. But please keep it FRIENDLY.
** New Info Added Below - Additional Options suggested by others:
Pre-formed Pond (JanetMermaid's list):
These are the ready to install single piece shells. Varies from the economical small units available at Home Depot, to the large pre-formed 1500 gallon pond available from WLim, which comes ready made for bottom drains and TPRs.
Pros: Inexpensive (unless you want Lim's unit which is over $2000 not including shipping), no wrinkles, puncture resistant, and DIY friendly.
Cons: Typically the water capacity is not sufficient for koi, unless you get the large one from Lim (!), shapes are limited to the pre-forms, so no mods possible.
Thoroughseal (SherryM's list)
Who makes it, what is it, how is it applied, any data on elongation or durability?
Cost: ?? Pros: ??? Cons: ????
Super Bond 8 (SherryM's list)
What is it? SherryM's pond builder likes Super Bond 8 more than Thoroughseal. Cost: ?, Pros: ?, Cons: ?
Pebbletech (SherryM's list)
Used for pool coatings, what is it? DIY friendly? Cost for SherryMs pool re-finishing is $5800. Pros: ?, Cons: ?
- Wayne, typed all of this with only one cup of coffee.