Underground siding against concrete?

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  #1  
Old 12-10-04, 08:42 PM
blkeagl
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Question Underground siding against concrete?

I have an unusual situation I could not find mentioned on the site or by searching the forums.

I have removed an old, poorly designed redwood deck that has caused extensive rot along the siding where the rim joist was incorrectly attached. It was about 16' by 14'6" and at it's deepest, it is 4' high. Due to improperly sloped ground, it slopes INTO the house, which is what I want to correct so that I can pave the crawlspace and use it as a basement.

I am planning on replacing the siding all the way to the foundation, and filling the depression with sand (not against the siding) and topping that with bent rebar and filling with concrete.

This was my concrete workers suggestion as I was originally planning on building a new deck, vapor sealing it and pouring a layer of concrete to tile it over. The first solution is actually less expensive and would result in a patio that connect to my yard (and proper drainage) better.

So I have 2 questions.

Is this approach sane?

Assuming that it is, what would be appropriate waterproof siding for me to install? I was thinking of 5/8th sheer wall OSB sheathing, some kind of housewrap, a layer of foam insulation, another layer of exterior grade plywood and then a waterproofing compound before we put in some forms for the concrete.

I guess an alternative would be to just install concrete forms and then side from the crawlspace (it's about 7' high from inside the foundation wall, 4' high from outside) like a traditional basement, but then we'd be waterproofing from the inside.

My third question, I guess. Any other suggestions?
 
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  #2  
Old 12-12-04, 09:49 AM
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Completely Confused

I've read this post several times and and left completely confused by what you currently have and what you propose to do.

Until you can clarify, I can only offer the following suggestions:

1) House siding should never be placed below grade. Codes require that all sidings be at least 8" above the ground with the exception that brick can be 4" above the ground. Therefore any attempts to place siding behind concrete or under ground is stictly forbidden.

2)House wraps are never used in conjunction with foam insulation panels. The use of one will prohibit the function and proper designed use of the other.

3)Damproofing and waterproofing of an exterior foundation wall below ground level is most commonly accomplished using bituminous (tar) like coatings and epoxies or impermeable rubber membranes.
 
  #3  
Old 12-13-04, 09:38 AM
blkeagl
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I'm confused by the suggestion myself, hence the questions. I understand code, and the reason for it, which is why I'm disturbed by this suggestion and trying to figure out a way to do it correctly.

Let me try to clarify. I have a square area off my kitchen (the house is an L shape around it). The grade slopes TOWARDS the house foundation dropping approximate 4 feet in about 16-20 feet. The problem this causes in our VERY rainy climate is that surface runoff pools against the foundation wall and seeps underneath it into the crawlspace/basement.

The correct solution would have been to build the foundation wall 7 feet high instead of the current 3 feet, waterproofed it, and filled the depression so that water runs off away from the house and basically turn the area into a patio with grade being 4 feet above the current grade at the deepest. This is my ideal goal.

What was done instead is to install siding down to the foundation (ok) and then a deck was built over this trouble spot, holding and preventing evaporation of years of runoff into the area. I tore off the deck which was so rotted and crumbly and it was still wet underneath even though it hadn't rained in months.

I have been advised against installing a french drain due to soil conditions and so I'm looking for another solution. The soil information I do have indicates that our water seepage issues are purely surface drainage, not rising groundwater.

I considered installing a new foundation wall before the grade drops down and waterproofing that and arranging surface drainage to do the right thing. Then building a new deck/floor using that outer foundation. The problem then would be waterproofing a new floorspace to prevent water intrusion which would just start the rot all over again. I considered waterproofing, a concrete pour or Durock, and then some unglazed tile. Not a good way to go, I think.

Perhaps this isn't really a siding question?
 
  #4  
Old 12-13-04, 05:18 PM
blkeagl
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Probably answer..

Just to not leave anyone hanging.

The right answer is probably for me to simply pour a new 7' foundation wall, tied into the old foundation and rip out the old siding that would be against the newly poured foundation (use it as a form) and tie the house into the new foundation.

That way new siding can come down the upper house, be properly flashed and tied into the foundation without coming into contact with the ground or any below grade surfaces. Right?

I guess I'll have a foundation specialist come and take a look.
 
  #5  
Old 12-13-04, 05:36 PM
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For the expense of building a new foundation wall, compare the cost of grading the yard and installing a drain. This will prevent the water from accumulating against the house, which is the problem. The essence of a drain is having it direct the water to somewhere else. The type of soil would be a concern only if there is a problem at the terminus of the drain.

It is more effective to solve the problem with the water puddlding than it is to try and seal the water out. Drainage and grading will solve the problem of the water and obiviate the matter of building a new foundation wall and sealing it.

Hope this helps.
 
  #6  
Old 12-14-04, 02:56 PM
blkeagl
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Thanks.

I realize that, but grading will not solve the entire problem due to the terrain. The house was poorly placed and the terrain was improperly graded some 60 years ago.

The challenge is now to correct the problem without rebuilding the house. By installing a proper new foundation wall, I could then grade the area (I have plenty of quality fill) and fix the drainage.

Overkill perhaps, but I was advised that a standard french drain would make the problem worse in a few years (due to my soil conditions). I'll look into it further.

But as I said, after a brief foray into the odd (and WRONG!) idea of trying to waterproof some siding down to the old foundation and then pour a patio against it, this is definitely not a siding question.

Thanks.
 
  #7  
Old 12-14-04, 03:01 PM
blkeagl
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Oops..

Chris, I re-read your post and realize that you are talking about either an open drain or below ground pipe, right, not a french drain.

This was actually my initial intent as long as it lets the area dry out well enough (under a low deck). My experience with decks in this area (CA redwood rainforest) is that they rot pretty easily, but I may yet go back to this approach if a new foundation wall is more expensive than drainage AND a new deck of composite.

Thanks again.
 
  #8  
Old 12-14-04, 08:12 PM
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French Drain

Actually I am for a french drain and see no reason one cannot be used.

Soil conditions have little if anything to do with proper implementation of a french drain because proper placement of a french drain employs several feet of crushed, washed stone over the tiles and around the foundation and has little or nothing to do with existing soil conditions.

A properly installed exterior french drain system will be able to handle both suface water runoff and any potential water table rises and is the wisest move possible, impo...

If you need more information about peripheral french drain systems, simply ask, because it is one of my areas of 'expertise'....
 
  #9  
Old 12-17-04, 11:42 AM
blkeagl
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Originally Posted by homebild
Actually I am for a french drain and see no reason one cannot be used.

Soil conditions have little if anything to do with proper implementation of a french drain because proper placement of a french drain employs several feet of crushed, washed stone over the tiles and around the foundation and has little or nothing to do with existing soil conditions.
The reason I was given for NOT installing a french drain is because of the ground. The drain would eventually fill with soil and leave a path for water to penetrate the foundation.

We have only 18 inches (more or less) of soil sitting on sandstone. We CAN carve into the sandstone (and did to for footings for some new exterior retaining walls), but water does not penetrate it very well and carving into it to install a french drain is considered unwise.

This is actually whay happened because as I was excavating this week along the foundation I found improperly installed drains (no tiles or crushed stone) that we comepletely clogged.

My intent was to install french drains only behind the retaining walls and daylight them into a nearby creek/drainage system (there's a drainage easement on record).

Originally Posted by homebild
A properly installed exterior french drain system will be able to handle both suface water runoff and any potential water table rises and is the wisest move possible, impo...

If you need more information about peripheral french drain systems, simply ask, because it is one of my areas of 'expertise'....
My understanding was that a french drain was not a good idea here because 1) it will bring water below the foundation when it wouldn't normally get there if we didn't excavate because 2) there is no rising groundwater problem since the property basically sits on sandstone and granite deposits. You can actually watch runoff for days and days on end after storms because it just cannot seep into the ground very far. Instead it seeps onto the road and my basement.

I have since discovered that an improper french drain was installed 20+ years ago and this is why I am getting drainage into the basement, so I guess I do have to install a proper french drain system now.

Is there anything I can do to reduce the likelihood of it clogging again in the future? I know about using soil fabric and lots of crushed stone to a few inches from the surface.
 
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