Waterproofing basment walls

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Originally Posted By: Mr Nice
If basements are known to be problematic...
Why build a house with a basement ???

Simple: The footings and beams need to be (far) below the frost line. Otherwise they'll heave, causing major structural problems.

Where you & I live, the ground doesn't come close to freezing, though a basement would be a GREAT place to escape the heat.
 
Originally Posted By: sleddriver
Originally Posted By: Mr Nice
If basements are known to be problematic...
Why build a house with a basement ???

Simple: The footings and beams need to be (far) below the frost line. Otherwise they'll heave, causing major structural problems.

Where you & I live, the ground doesn't come close to freezing, though a basement would be a GREAT place to escape the heat.

You can build on a slab up here but it needs to be engineered, our friends did this and it seems to be working just fine. They insulated with R10 Styrofoam up the edge of the slab and 4' out from the edges which keeps the ground underneath thawed year round. They have a few normal hairline cracks but no movement so far.
They do wish they had a basement sometimes though, as its the cheapest heated storage space you can build given a well drained site.
 
Thanks for technical explanation.

There has been a few BITOG members posting about leaky basements. Here in Florida were are so close to water table no way to have a basement.
 
in Michigan we have clay and very clayish soil,
water will find the weakest spot in your concrete and come right in.

what KDOAXS posted above is the correct solution but expensive,
it is expensive even to do that in a new construction.

Cheaper option: sump pump.

1. Rent something to cut hole in your foundation,
2. install sump pump system.
3. Drain water out of the house as far away as possible.

I am going to attempt the same but outside, yes, a sump pump outside as I don't want to cut and create a hole in my garage.
My garage is below grade.
 
Originally Posted By: stockrex
in Michigan we have clay and very clayish soil,
water will find the weakest spot in your concrete and come right in.

This. At the footer you will have about 3 psi water pressure. If you don't think that's a lot I have a bridge I will sell you.
 
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Backfilling with clay soils is the #1 way to ensure water problems in a basement construction. Water can't be stopped, it has to be managed, and when you backfill with an impermeable soil, it traps the water against the basement walls and like stockrex mentioned it will find a way in.

Here in southeastern Wisconsin most of the soil is clay and there is a lot of surface (perched) water around. When you dig a basement that perched water goes right in, and unless you manage it you're only going to have problems. The right sort of backfill is with rock, and many builders excavate the basement floor down to the foundation level and fill that with rock too. All of which will permit an orderly drainage to the foundation drains where it can be collected in a sump (one or more) and be drained away. It's the only way to manage it, you can't stop the water.

Plus like everyone else mentioned, proper grading to keep as much water away from the foundation is also critical. If the elevation that was set during construction is not correct (too low) then you are going to have problems no mater what. But a nice slope away from the house (the first few feet being an impermeable clay cap) works wonders.
 
Originally Posted By: Al
This. At the footer you will have about 3 psi water pressure. If you don't think that's a lot I have a bridge I will sell you.


I have a friend in a nearby community that has the native clay soil backfilled against his basement walls. When it rains he has a series of little fountains shooting out of the basement floor/wall interface. If it wasn't so serious it would be funny.
 
Originally Posted By: sleddriver
Originally Posted By: Mr Nice
If basements are known to be problematic...
Why build a house with a basement ???

Simple: The footings and beams need to be (far) below the frost line. Otherwise they'll heave, causing major structural problems.

Where you & I live, the ground doesn't come close to freezing, though a basement would be a GREAT place to escape the heat.


While that is true, you can also have footings and no basement, just a crawl-space. Quite a bit less construction cost.

Full basements always have the potential of water problems. Pretty much every basement will have a water problem at some pint. I've never experienced what Al has described above, only minor weeping and leaks, that were easily rectified.

Worst issue I had was a plugged drain tile that required popping a hole in the floor and replacing a section of cracked/plugged drain tile. The outfit that did the repair for me, also attached a 4'x8' plastic panel on the wall in that spot, that extended below the floor level. They pumped grouting goo through the wall to the outside in that spot as well. That repair was close to a grand ~15yrs ago.

KDO's water-proofing job is awesome. What I don't like about those is, you'll never see the whole picture of what's going on behind the panels covering the concrete walls.. Then again, in a finished basement, which is what this is all about, who cares. As long as it stays dry for a lifetime.
 
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Originally Posted By: Mr Nice
Thanks for technical explanation.

There has been a few BITOG members posting about leaky basements. Here in Florida were are so close to water table no way to have a basement.


It could be done, if done right from the beginning. It would also make a great hurricane shelter. Problem is to make a house water tight to prevent it from being flooded. No one likes living in an Igloo.
 
Originally Posted By: JTK


KDO's water-proofing job is awesome. What I don't like about those is, you'll never see the whole picture of what's going on behind the panels covering the concrete walls.. Then again, in a finished basement, which is what this is all about, who cares. As long as it stays dry for a lifetime.


That was our objective, to make sure we never have another water problem again once the basement is finished. The previous owner had halfway finished it, but we had to gut it all because of the water and mold. If they had taken the time to properly install the drain tile when they built the house, it probably never would have been an issue. Yes, it was expensive, but it's guaranteed for life and the warranty is transferable if we ever decide to sell.

They also installed this "Triple Safe" sump pump, which as the name suggests, contains 3 separate pumps. It has the main pump, a secondary pump that kicks in if the first one fails or can't keep up, and a battery backup pump. It also has an alarm that goes off if the water level gets too high.

 
I'm the only certified wood basement builder in the province. Cheap,completely waterproof and engineered forever.
But the backfill is the key. We run a sock covered weeping tile around the footing,tying it into the sewer line. Backfill is 3 feet of crushed rock,4 feet of sand then topsoil.
In the 20 years I've been framing these not one has EVER had water intrusion,not one.
Concrete foundations tend to be done by guys who just want to get paid. I've seen countless poor quality foundations that end up wet because there is little oversight. Wood foundations are different. Everyone is looking hard to find defect to which I allow none.
 
Originally Posted By: Pop_Rivit
There's nothing hard about removing a deck, pulling it out of the way, correcting the grade, and then putting the deck back.

crackmeup2.gif
That's easy for you to say. And I bet you wouldn't do it.
 
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Originally Posted By: Warstud
Originally Posted By: Pop_Rivit
There's nothing hard about removing a deck, pulling it out of the way, correcting the grade, and then putting the deck back.

crackmeup2.gif
That's easy for you to say. And I bet you wouldn't do it.



No kidding.

I'm an inter-provincial journeyman carpenter. I can say from experience that it's not that simple or easy and to imply as such is absurd.
I've also moved houses from one foundation miles away to another. It's not just that easy of just cutting it loose and moving it.

But ole pop is expert at everything.
Lots of talk
 
Thanks KD0AXS for the Pics

My question is for post #3741390...it looks as though the company you had do the job... put in drain tile...filled with gravel...put in plastic dimple board ...and cemented over it. What's the purpose of the dimple board. Plus they cemented over it. I dont get it. Explain?
 
Originally Posted By: Warstud
Thanks KD0AXS for the Pics

My question is for post #3741390...it looks as though the company you had do the job... put in drain tile...filled with gravel...put in plastic dimple board ...and cemented over it. What's the purpose of the dimple board. Plus they cemented over it. I dont get it. Explain?


The dimple board sits on top of the footing. The "dimples" create an air gap which allows water to flow under the slab where it can make its way to the drain tile. Maybe a little easier to see in this pic.

cactusboard-beauty-shot.jpg
 
Does the french drain work at all? We live in an older home, and had some moisture through the walls. Once or twice we saw the water table get high enough to barely come up from the bottom as well.

Our home never had a French drain or a sump hole. We had one installed. Just doing so must have re-adjusted the water dynamics under the slab enough that it was never damp again. And though the water level has risen under deluge conditions (e.g. hurricanes), the sump pump has never come on to move water.

So there may be some very basic flow issues under the slab which could redistribute how water stands and builds pressure.

But if you have a grading issue, then that is something that should be dealt with first. I get it that removing soil around would be a major consideration. On our home, it would have meant remiving major hardscaping and other features on three sides of the house, which I estimate at minimum to be $30k worth of work before we would even get to the task of digging out the foundation and waterproofing. While Id consider it if necessary, fortunately it wasnt for us.

So get the slope right where you can by adding or removing soil, extend downspouts or even completely re-locate their exit location to a well or something if need be, and see how that works out. Also consider if your internal drain works properly.

But always keep in your mind the possibility of needing a major effort performed. It is always a possibility, though sometimes the "gamble" of a few well thought out approaches prior to that may be prudent.
 
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