Replies

1. 
   Guest_ | Apr 03, 1999 06:39am | #1

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   I've use two coats of Tamoseal witch is a brush on product that comes in a bag and mixed with water, followed by 2 coats of Bitumin damproofing sprayed on below grade. The joint at the footing and foundation wall must be cleaned and sealed carefully.

   Here in Augusta Co. VA, we use block and brick foundations as we wait for a poured foundation contractor who can get them square and level with correct dimentions. I go around the footing with a little sand before the block goes up. This catches the excess motar that is cut off. After the block is done, I shovel the sand away from the block and proceed with the coatings.

   Before backfilling, a foundation drain is carefully placed around the perimeter covered with a layer of crushed stone and then filter fabric.

   The final step is proper grading to run surface water away from the house. We also use buried ADS solid pipe to move roof water from the downspouts away from the house to grade.

1. 
   Guest_ | Apr 03, 1999 08:41am | #2

   *kcoyner:Where is Augusta Co. VA? I lived in VA most of my life and don't know where that county is. Just curious.

2. 
   Rob_Dykeman | Apr 03, 1999 05:19pm | #3

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   Waterproofing is an important part of any foundation. There is a very good article in this month's Permanent building and Foundation Mag. If you don't get the mag you can read the article on their web site http://www.pbf.org

3. 
   Guest_ | Apr 05, 1999 09:37am | #4

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   Augusta Co. is the biggest and oldest county in Virginia. The Cities of Staunton and Waynesboro lie in Augusta Co. It is just across the Blue Ridge from the land of Jefferson (Charlottesville) about 25 miles west.

4. 
   Scott_Lewis | Apr 05, 1999 12:39pm | #5

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   Dear Rob,

   Thanks for your recommendation of the article on basement drainage. I've just read it, and it's given me a couple of new ideas about how I want to design the drainage system. I'm still trying to figure out, however, what kind of waterproofing compound or substance I should put on the exterior of the foundation. Any ideas?

5. 
   Guest_ | Apr 06, 1999 12:30am | #6

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   The problem with most foundation coatings that are sprayed or brushed on is that they crack with the foundation. Over time as buildings settle the foundations almost certainly develop small hairline cracks at best or worse big cracks. The bigger the crack the more the membrane has to stretch to bridge the crack and is more likely it fail. Another problem is during backfill, rocks and sharp debris can damage coatings rendering them useless.

   The major cause of water penetrating basements is hydrostatic pressure, especially in poor draining soils (clay is probably the worst). On one of my projects years ago (I was the framer) the general contractor forgot to have the foundation contractor put a sleeve in the form before pouring for the water supply to come into the basement. We were at the backframing stage So the foundation had been backfilled (with clay) for some time. The backhoe was coming the next day to dig the trench and run the waterline from the well to the house. The general proceeded to drill a hole through the concrete foundation for the waterline (trench not dug yet!!). I asked him if he wasn't concerned about water coming into the basement through the hole he was about to drill. He said no but just to be safe he would drill the hole on a downward angle. I chuckled to myself and let him proceed with the hole. When the drill went through the wall water started seeping around the drill bit, he pulled the drill out of the hole and the water gushed out of that hole about three feet into the room. The look on his face was priceless. I helped him get the hole plugged but not before about 250 gallons of water had covered the basement floor. The moral of this story is never underestimate the power of hydrostatic pressure.

   I recommend an air gap barrier to my clients (here on the southwest coast of British Columbia). It is a heavy plastic sheet with thousands of dimples pressed into it. This creates an airspace next to the foundation allowing any water to drain down to the perimeter drainage eliminating the hydrostatic pressure against the foundation. The critical thing with this product is proper installation. Sealed properly at the top and run over the footing at the bottom. It is fastened with special concrete nails and washers that fit into the dimples. There are several manufacturers of this product here in Canada, one even has a filter cloth attached to one face of the dimple board. System Platon, made by BIG'O' is available south of the border. You could check with your local BIG'O' supplier or you can look them up on line at http://www.big-o.com/platnes.html We also install a coat of water based foundation damproofing on the wall prior to the air gap barrier.

   Good luck I hope this helps

6. 
   Scott_Lewis | Apr 06, 1999 04:50am | #7

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   Dera Albert,

   Thanks for your message with the convincing story. Yes, I would agree that air gap barriers seem like the most protective way to go in that, along with a properly working drainage system, they help relieve the hydrostatic pressure against the wall. What I am looking to find out now (and I realize that I didn't express it well in my original question) is what kind of additional waterproofing or dampproofing agent would work best as added protection on the foundation (behind the air gap barrier). Any experience with any of the products mentioned in my original question?

   Thanks.

1. 
   Tom_Laing | Apr 06, 1999 09:16am | #8

   *Scott,Lots of information in these responses, but not many that answer your questions. Most the builders in my town, Homer, Alaska use a product called Bituthene. I've used it on several jobs without a callback. All the suppliers up here carry it. It's 60 mils thick and comes in a 3' wide roll. It will self-adhere to some surfaces, but is normally used with a primer, which is somewhat like a contact cement. The primer is rolled on the clean, dry wall, and allowed to dry a few minutes. The membrane is best installed vertically, and takes two or three people to put it on, because once it touches the primer, or another piece of Bituthene, it becomes one with itself! You wrap it down over the footing to below the level of the drain tile. It's best to cove the place where wall meets footing because its hard to get the 90 deg. fold without creating an air void behind it.Tom Laing

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   Scott_Lewis | Apr 06, 1999 08:05pm | #9

   *Tom,Thanks for your recommendation. I'll look into it.Scott

1. 
   Barry_Giles | Apr 07, 1999 07:19am | #10

   *ScottAs far as I'm concerned Bituthene rules. The only addition I would add to Tom's note is that I've covered the Bituthene prior to backfill to protect it. I used sheets of 1" expanded foam just so that rocks etc don't go thru. However anything that looks right, dosn't rot or harbour insects will do great.Barry

7. 
   Scott_Lewis | Apr 07, 1999 07:19am | #11

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   I would like to know the most effective and durable way for waterproofing a basement foundation. I am aware of some new products, but don't have any experience with them. Is anyone familiar with the performance of any of these waterproofing products?:
   1) "Aqua-Guard" or "Hydro-Guard" (brush-on products by Hydro-cell, Inc.)
   2) bitumin modified urethane products (brush-on)
   3) bentonite products (panels, rolls or spray-on)
   4) crystalline cementitious products (brush-on or spray-on)
   5) membranes.
   I've heard excellent things said about each of these products. Does anyone know which, if any, perform best? I'd also like to know where I can buy them.

8. 
   Guest_ | Apr 07, 1999 07:19am | #12

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   Scott.

   Sorry about that, I thought you were also looking for alternative products or methods.

   Unfortunately I don't have any experience with any of the products you mentioned. In the area where I live now (southwest Coastal B.C.) there is very little soil, mostly rock. Therefore our backfill material is very rough on applied coatings.