Rebuilding (and improving) a 1940s stone foundation?


  #1  
Old 09-15-09, 06:36 PM
M
Member
Thread Starter
Join Date: Sep 2009
Location: Kentucky
Posts: 16
Received 0 Votes on 0 Posts
Rebuilding (and improving) a 1940s stone foundation?

I am preparing to renovate a 1940s cinder block building that is located on the side of a hill.



One of the first things I would like to take care of is a presumably long-standing drainage problem along the lowest two exterior walls. The best way I can describe the shape of building is a blunted wedge. The long wall pictured above intersects with the short side of the blunted wedge:



The corner of these two lowest walls has the worst of the water damage which is responsible for a stress crack which we want to keep from worsening.



The corner itself is in a sad state, the mortar having disintegrated leaving a void where the rock has fallen away.





Looking up the longer wall, there is a lot of dampness and there is the same issue with the foundation eroding, though nowhere is nearly as bad as the corner.



Maybe it has something to do with the fact that the downspouts aren't taken away from the building at all.



Of course being built right into the hill doesn't help things.


There are a few more photos at Gallery for folks who might be interested.

I met with a general contractor who has no financial stake in this project, and after looking it over thoroughly he felt that I should take up that wooden walkway along the long wall, excavate down a couple of feet and then build back out the foundation in concrete, pulling away some of the rock when necessary to form a kind of apron which would not only give form to the foundation but carry water away from the foundation.

He suggested that angled/bent rebar be drilled into existing foundation at regular intervals to establish the structure of the "apron." Does this make sense? I'm a layman in matters of concrete and masonry and I'll be hiring someone to do this work.

Can anyone offer some advice on what I should listen to when meeting with contractors to look over the project? Any techniques which I should insist on or consider a red flag when I get a bid?
 
  #2  
Old 09-16-09, 07:10 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
Digging was the first thing that came to mind as I read your post. There is no way around it. I agree with removing the wooden walk too. I would expose as much of the foundation as possible, down to the footing, build it again & seal it with a membrane before backfilling. Extend the downspouts or maybe add dry wells. Use french drains around the building if needed.

Insist on everything in writing with a work time line & a payment time line. Try to leave the final third of the payment upon completion.
 
  #3  
Old 09-16-09, 07:42 PM
M
Member
Thread Starter
Join Date: Sep 2009
Location: Kentucky
Posts: 16
Received 0 Votes on 0 Posts
Originally Posted by Pulpo View Post
Digging was the first thing that came to mind as I read your post. There is no way around it. I agree with removing the wooden walk too. I would expose as much of the foundation as possible, down to the footing, build it again & seal it with a membrane before backfilling. Extend the downspouts or maybe add dry wells. Use french drains around the building if needed.

Insist on everything in writing with a work time line & a payment time line. Try to leave the final third of the payment upon completion.
Thanks for the help! I've read some of your other posts here and I appreciate your advice. I'm trying to be sure I'm up on the terminology you're using:

Footing - Intuitively I understand this is probably whatever is at the bottom of the foundation. Beyond that, do you have any thoughts on how far this is likely to extend below the bottom of the cinder blocks? Is there a particular way that footers for this type of foundation are likely to have been built that I can expect to see?

Membrane - When we talk about a membrane for this foundation, are we talking about sheets of impermeable material between the newly-surfaced foundation or something more like a sealant that is applied to the surface of the new concrete?

I never knew what a dry well was called until your post led me to do some searching. Good to put a name to that item. That will obviously be more intensive than extending the downspouts, so is there any criteria you would suggest that would lead you to choose a dry well? I'm seeing that there are some manufacturers selling pre-fab plastic dry wells, and easier is always appealing. Having never installed a dry well I don't know if that is a Bad Idea though.

Again, thanks for the help, and if you do have a moment to follow up feel free to just give me enough ammunition to work with google like I've done with the dry wells.
 
  #4  
Old 09-17-09, 07:03 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
Footing: That's right. We're talking about the bottom of the foundation where it extends a few inches out from the wall. I used to do a lot of waterproofing & we would dig down a few inches past that point & seal it with the membrane. You can get an idea how far down that is buy the height of the cellar.

Menbrane: It comes on rolls. It's a heaving duty composite that gets sealed to the foundation from the footing to a few inches higher than ground level. I have never used it on anything but a smooth foundation, so check with the building supply people.

Drywell: If you can extend the downspouts far enough, you probably don't need drywells. How is the dampness in the cellar? Are there any signs of water? Pay particular attention to the side of the building that high on the hill.
 
  #5  
Old 09-17-09, 07:40 AM
M
Member
Thread Starter
Join Date: Sep 2009
Location: Kentucky
Posts: 16
Received 0 Votes on 0 Posts
Perfect, I'm reading you clear on the footing and membrane then, thanks for that. I'll check with our builder's supply on the membrane as you suggested.


Drywell: If you can extend the downspouts far enough, you probably don't need drywells. How is the dampness in the cellar? Are there any signs of water? Pay particular attention to the side of the building that high on the hill.

There is a fair amount of dampness in the cellar, though it looks to me like it is most focused where the damage on the exposed foundation is the worst. There is a floor joist running up to that corner which is pretty badly damaged from the moisture which I intend to replace.

I will make another visit to the building to look closer at the side that is up against the hill. There is no cellar under that top third (or even half) of the building, but there is, for lack of a better term, a "vertical crawlspace" which allows access to the area between the wall and the rock.

The second floor extends farther up the hill on the top side (it's a kind of utility room space) which does have some dampness, but I'm not sure if that's more on account of the water coming off the hill or the fact that there are 'windows' in the block which are just screened.

If I can get some photos of the top side I'll add them to the thread, it would be great to get any thoughts you have on that since it does make sense that we could have water there too.
 
  #6  
Old 09-17-09, 12:27 PM
Join Date: Mar 2005
Location: USA
Posts: 6,130
Received 0 Votes on 0 Posts
Rebuilding (and improving) a 1940s stone foundation?

You have an improperly designed and built building that has suffered from severe "deferred maintenance".

The building is being flood from above and the site conditions are causing the foundation to deteriorate at a rapid rate.

If you do not fix the roof, flashing and gutters all the membranes and waterproofing around will not do the job. There has been long term moisture leakage into the top of the wall and it ends up saturating the entire structure. Membranes and waterproofing the exterior are just short term "band-aids".

Since this is broadcasting facility, the site may be necessary to use. Long term repairs may cost more than a new properly built building somewhere else on the site.

The gutters are too small, disconnected and probably plugged in spots. The downspouts are also too small by looking at without any real dimensions.

Since you are on the side of a hill, getting drainage should be easy with downspout extensions above or below ground.

You should contact a structural/soils engineer before you go too far.

Dick
 
  #7  
Old 09-17-09, 02:46 PM
M
Member
Thread Starter
Join Date: Sep 2009
Location: Kentucky
Posts: 16
Received 0 Votes on 0 Posts
Originally Posted by Concretemasonry View Post
If you do not fix the roof, flashing and gutters all the membranes and waterproofing around will not do the job. There has been long term moisture leakage into the top of the wall and it ends up saturating the entire structure. Membranes and waterproofing the exterior are just short term "band-aids".
Is there any chance that the damage you're seeing predates the current roof? What you see in that photo is a rubber roof that was put in about 12 years ago and seems to be pretty well sealed.

I agree it would be better with larger gutters and downspouts, but I have worked around the perimeter of the roof and the gutter does seem to have a good fit all the way around.

Is there a way to calculate the necessary capacity of the gutters and downspouts based on the surface area of the roof? If so I could easily get those measurements and see if we need to look at some upgrades up top.

Thank you very much for bringing a new element to the discussion! (Even if it is not one I'm glad to hear)
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: