Odd drainage issue needing creative help

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by grendlesgirl, Apr 3, 2007.

  1. grendlesgirl

    grendlesgirl New Member

    Hello - I am a falconer and I am looking for some help in creating a system to keep water from accumulating on the floor of the chambers that my hawks live in (called Mews). I have an 50+ year-old 19 x 19' wooden building with a flat concrete slab base that I have converted into two hawk houses that are seperated from each other with a plywood wall.

    I would like to have a pea-gravel floor for the mews because it is good for the feet of the birds and won't damage their talons however there is no drain in the concrete and if the water sits it can form bacteria which is deadly for the birds as it causes aspergilliosis. Gravel is also easy to clean and disenfect with a hose sprayer when there is a way for the water to drain out. Currently I have astroturf over the bottom of the mews which is hard to clean and after a while not very sanitary and expensive to replace.

    There are two very large open-air windows so slight moisture or temporary dampness is not a worry (I live in a dry area), however, I would like to have some way to channel water off of the surface of the concrete under the gravel when it is hosed off 2 times a month.

    And to make things more complicated -
    I know very little about concrete or installing drains - I'll probably do more damage with a jackhammer than help.
    I would like to find something cheaper than 200 bucks.

    I had thought about just drilling some holes where the concrete meets the wood along the sides but I have a felling there is a better solution out there. I found this site when I was googling trying to find an answer. Any good ideas out there?

    Thank you!
  2. Slope your floor. Plan your slope.

    assuming you are handy with tools.

    use a level to find where the floor is flat, where sloped. Draw a scale drawing, showing your current drainage "pattern", and then plan how you would wish a perfect setup would be for your situation. Post these two, along with enough information so people here can get an idea of whether an alternative route for water to flow would be easier to build.

    assuming you know water only flows downhill.

    david :D
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    Can think of a couple of things that would work, but not for $200. To ensure water drains, the floor should be sloped, sort of like a huge shower stall. The drain doesn't have to be in the middle, but it might be most efficient there. For proper drainage, you'd sort of like the same thing a drain pipe needs - 1/4" per foot, or about 3.25" from the corner to the center. You'd want that to be some material that wouldn't absorb odors, wouldn't rot, and is strong enough. Tile would be nice, but even cheap floor tile is more than twice that, and you still haven't got your slope. You could build a wood sloped floor and put a waterproof membrane - sort of like a flat roof down. Some of them are designed to have a rock/gravel bed on top of them and are pretty tough. If you built the floor up high enough, you could put a drain and drain pipe in it, but unless you cut at least some concrete, assuming you put in a trap (a good idea!), it would have to be fairly thick. How much headroom do you have? Some patching concretes can be bonded to the existing subfloor and can be feathered out thin, but again, don't think you could do it for that size building for close to that price point. Not sure how durable that stuff is. If you decided to tile it, to get the taper, you could use what is called deck mud - the stuff they use to make a tiled floor for a shower - it is a dry mix of 5 parts sand to 1 part concrete. Think wet beach sand that will hold its shape. You'd need lots of it, and it's not light, but it is cheap. You can't just leave it, as it is very porous and not that strong (the result of all that sand), but holds tile quite well, and is great in compression.

    Note, depending on where you live, you might want to drain that into a drywell, or if convenient, into the sewer line.

    Maybe some others will have some ideas.
  4. leejosepho

    leejosepho DIY scratch-pad engineer

    If that floor is fairly flat, one thing you might be able to do is to cut some (actually many) grooves in either a grid-like or star-burst kind of pattern coming together at a low spot that is hopefully close to a wall, then cut a hole in the floor at that spot and install a sump that could either be drained via gravity or pumped out to send the contents elsewhere. A saw to do that can be rented, but it would likely be far too noisy to use with your birds nearby.

    Grooves (in the place of slope) in the floor would make it possible for water on the floor's surface to drain off from around the gravel and flow away, but those grooves could also become clogged with "fines" (such as dirt, dust, seed casings) of whatever kind.
  5. After you map out your existing slope, your idea of sending the water outside by cutting perimeter holes is still a good option to continue with. It'll be inexpensive to use a Portland cement product to build up a slope in the right direction to accentuate the natural flow. The slope could be all in one direction, so the entire room is "sloped" all the same way. Then, you don't need plumbing. The slope could be half what is prescribed for showers, so that'd be only three inches higher at the high end of the 19' floor.

    Imperceptible if the entire floor is flat and sloped. Grooves can be good too. They help a lot if the floor is not highly sloped.

    Then, a paintable (trowelable) waterproofing membrane can go on top to ensure the moisture goes outside and to prevent moisture from seeping into the concrete especially at the low (wet) side.

    Deck mud is not the right recipe unless you want to raise the floor by at least one inch everywhere. Not your goal. Another cement product will be fine; it'll have another name but still be just as cheap and heavy. Even if you want to tile the floor, deck mud is not the right product (unless you want to raise the floor by at least one inch everywhere).

    Your budget is reasonable, imho.

    First, the slope. Second, waterproofing the wet end. Third, you can add pea gravel in some areas.

    Without the slope, water is seeping into concrete and not running off. Moist concrete is a prime material to grow bacteria (and diseases) in. If you don't slope the floor, anything else you do will aggravate the moisture retention.

    Last edited: Apr 3, 2007
  6. Bob NH

    Bob NH In the Trades

    New Hampshire
    Anything like pea gravel on concrete is going to eventually get filled with droppings that are hard to wash out. It will also be hard to drain and dry, no matter what you do for slope.

    You could make a raised deck on pressure treated material and cover it with hardware cloth ( 1/8, 3/16, or 1/4" welded wire mesh). If the mesh is not good for their feet, then you could cover it with a thin layer (maybe 1/2") of pea stone to limit the weight.

    If it is well off the floor, you could hose the top down, let it drain, and get good circulation through the ventilated space below it to dry it. You might use an exhaust fan to pull air down through the gravel/screen layer and dry the floor underneath. In a dry climate it would not take long to dry it.

    You probably want to let it drain around all edges so you might have to cut spaces in the plate or sill if there is a plate or sill.

    I would consider something like 2x6's set on the concrete spaced as far apart as possible consistent with holding the hardware cloth and gravel. You might even be able to get by with splitting the 2x6's if you think that is high enough.

    If you don't have to walk on it and you don't need gravel on the mesh, then you could use the 1/8" mesh on very light supports. You might put a few "stepping stones", such as bricks, under the mesh at intervals so you could walk in if necessary.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    You'd only want to use the deck mud if you were going to tile it...Sloping it only in one direction is certainly an option. I'd still plan the approximately 1/4" per foot, though.
  8. grendlesgirl

    grendlesgirl New Member

    Wow thanks for all of the great ideas in just a couple of hours! This has been something I have been trying to figure out for the last two years. I would like to try the slope idea with perimeter drains. Is it very diffcult to slope concrete? I have never done anything concrete but this could be a good way to learn. Maybe I could finish my basement next or make a bomb shelter. Are there special tools that I need? (I know Home Depot will try to sell me everything).

    If I slope the concrete should I put grooves in it as well or is that too much of a pain? I'm thinking if the concrete will allow it to set in PVC cut in half with screen over it? Of course I don't know anything so I welcome anyone saying that it is a bad idea.

    I used to help out as a a volunteer at the local endangered raptor center. We would clean the mews gravel out every week (they had drains) with spray water with a bleach solution. If you clean it frequenly enough the mutes (poops) don't collect because they are mainly uric acid. So you don't have to use much water either. But if you let it sit for a long time and build up it becomes nearly impossible to even scrape off - which is why I want to get rid of the astroturf.

    The birds can go outside when I'm working in there they are falconry birds so very used to people. Here is a picture from today where my newest bird caught his first bunny.


    Please send me more ideas! Thank you!! I will have to send a picture when it is done. . .

  9. After stirring yoghurt and paint, you are experienced enough to mix concrete and water. (Sand is still the main ingredient in all mixes). I figure you'll either need an experienced person to help you buy enough bags, and get all 361 square feet sloped evenly, or you'll need to do this project so slowly that this thread will become the page your browser points to every time you open it.

    Whatever mix of screen, material, or pebbles you design for the birds' feet, on a drainable floor, might be best made as a separate system, not embedded in the top layer of concrete.

    Drains at the edge, means that the wood sill plate should be painted with liquid membrane too, where it meets the concrete. That'll be sufficient protection for the wood parts of a falconry in a dry climate, imho. Falkonerei, fauconnerie and falconry are all the same word; did you ever notice that? :)

    The steeper the slope the faster water slides away. Water slides on a slope as low as 1.5%- 2%; at this small slope, the roughness of the surface is now beginning to be a factor; water still moves but slowly. If the slope is 4%, surface roughness is no longer important.

  10. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    You might just have to pour a floor topping which slopes to the perimeter, either into a perimeter trough or just out onto the surrounding ground.
  11. Bob NH

    Bob NH In the Trades

    New Hampshire
    Concrete is expensive and not easy to work with unless you have enough people with knowldege and strength. Enough concrete to allow you to get enough slope and drainage could cost $500 to $1000 off the truck.

    You could get quite a good slope at reasonable expense if you put about 6" of sand on the concrete at the center and shaped it to provide a slope toward the edge. Then cover it with a waterproof membrane such a 6 mil polyethylene.

    You could put PVC collector pipes in the low spots in the sand, on top of the polyethylene. Then cover the whole thing with pea-gravel.

    I would be inclined to make it like a pyramid, 6 to 8 inches high at the center, sloping away to zero at the edges. That would give you more than 1/2" per foot of slope. Put drain holes at the edge to get rid of the water.

    You could wet the sand to produce a sand castle packing condition and then screed it off to shape it to drain. Then install the polyethylene and cover it with the pea-gravel. The sand should be well tamped before you cover it so the plastic doesn't get sags from the weight of the stone. If you mix a little portland cement with the sand it will harden it from just the moisture in the sand so you can walk on it without deforming it, but it won't be like concrete.

    When you add the stone you can improve the drainage by putting down a layer of coarse stone first, and then cover it with the finer stone. You should try to get river stone rather than crushed stone so it doesn't damage the plastic membrane.
  12. things to do to help decisions be made

    hi kelly!

    find out what cement products are available to you in your area. Go see them in a big store. Then, call the cement manufacturer for a recommendation. One option is a sand pile with the least possible amount of cement in it. Another option is the thinnest layer of concrete (i.e. "sand+cement+water"), so thin that is only feather thin at the low wall side, and still only X inches at the high side. Ask them how many bags will make 30, 40 or 50 cubic feet of volume. Find out whether the result you want can only be achieved by mixing it all in one go, or whether you can layer it, mixing small batches every so often. I have done this, troweling out several layers to build up a high end of a sloped floor, and I got the cement manufacturer's blessing first. Tell the cement company what your options or ideas are. All the options presented above are good options to consider.

    In a dry climate, hosing down a floor 20 - 30 times a year means your floor will dry out a lot between hosings. It is reasonable to say it will completely dry out between hosings. Keep that in mind when you decide what to implement. If a friend were to offer you oil paint for free and tell you it is practically as good as a waterproofing membrane for this application, s/he is not wrong. Since this slab is not subject to constant humidity or moisture, and probably not even any significant ground water either. (?).

    edit: P.S. All concrete is porous and bacteria reside in these pores. Larges scale pig farms lose a lot of young animals to concrete-residing disease which cannot be removed or disinfected. The pores of concrete have to be sealed with something, not left open. Perhaps it'll never happen to your birds, but this is the primary reason to ensure the concrete doesn't soak up water and organic crud. Recurring diseases.
    Last edited: Apr 4, 2007
  13. jrseaberg

    jrseaberg New Member

    central IL
    paint source...

    Having read the idea of oil-based paint, you might contact your local government/solid waste/environmental department to see if they have paint recycling. The city where I live does, and they will donate paint that has been turned in for recycling. They also screen/filter the paint before giving it out so it does not have the dryed-out goop at the bottom.

    Just a thought.
    Jim S.
Similar Threads: drainage issue
Forum Title Date
Plumbing Forum, Professional & DIY Advice Backyard Drainage Issue Aug 31, 2014
Plumbing Forum, Professional & DIY Advice Possible Drainage Issues - Beko Dishwasher Apr 7, 2013
Plumbing Forum, Professional & DIY Advice Toilet Overflow/Drainage Issues - 1 Bathroom Only Aug 22, 2011
Plumbing Forum, Professional & DIY Advice Drainage issue Apr 16, 2009
Plumbing Forum, Professional & DIY Advice Drain Pipe Sizea and Maximum Drainage Fixture Units. Sep 6, 2014

Share This Page