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Plastic Concrete over PVC Liner – 08/26/09
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 well,
and
have a few questions:
<Go ahead>
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 place.
<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.
<Yes>
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 concrete...>
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 material?
<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 twisted wire>
Chicken wire in my area is not something I find as a specific product,
<Can be called "wire mesh"... again, is at all HD's, Lowe'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 about...>
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 Faulkner
<Tammy, do look about... Craig's List, online directories, the Yellow
Pages for folks with experience to lend you insight here. Bob Fenner>
Plastic Concrete? - 06/05/09
Greetings Bob,
<Dennis>
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
waterfalls.
<Okay>
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 clean up>
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.
<Can>
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
Bob,
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
project.
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 – 05/02/09
Just wanted a little clarification on this Liner and
Concrete Pond Construction FAQ:
"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>"
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 proposed
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.
Carole
Thanks
<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:
http://wetwebmedia.com/PondSubWebIndex/pdlinerfaqs.htm
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 in
permanently those cobbles. BobF>
Re: Help, don't understand
FAQ response – 05/03/09
You are fantastic! Here is the link - item is about half-way down:
http://www.wetwebmedia.com/pondsubwebindex/pdconstfaqs.htm
thanks again
<Ooohhh... 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 Fenner>
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 Fenner>
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 Fenner>
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:
http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
the pieces in the tray under "Construction" re Liner Use. Bob Fenner>
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>
Cementacious 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, cementacious... alkaline. Please read here:
http://www.wetwebmedia.com/PondSubWebIndex/conclnrconstpd.htm
and:
http://www.wetwebmedia.com/PondSubWebIndex/acidblchpds.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:
http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
You might avoid a good number of future issues by studying now... Bob Fenner>
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 Pool Consulting
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. Bob Fenner>
Pool slide
I have just shotcreted my pool and in ground slide. Do I need to browncoat
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 Fenner>
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 90°. 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 Index":
http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm re 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 brown
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>
have a good one.
Jim
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