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Floating/suspended porch - concrete/joining issues (pics)

Posted by avesmor (My Page) on
Mon, Feb 14, 11 at 11:23

I hope this is the right forum for this. If not, my apologies in advance. We could really use some advice!

A little info to help: our house is three levels. The middle level is the entry level with a porch. The bottom level is unfinished, and includes a floating/suspended porch area (the ceiling of that area is the belly of the porch).

We came home this weekend to find the floating porch completely flooded. We've had a lot of snow, and it was warm enough this weekend for it to melt. The porch is covered so normally it doesn't get very wet, but it did get snowy, so the melting snow provided its first real exposure to heavy water.

Here's the layout of the entry level. The floated porch has the exact footprint of the porch you see here, and is directly below it:

We've noticed one thing that really scares us, and two more that might scare us if we knew more about concrete work. I'll list the problems below, and then add another layout pic with the areas shown to help conceptualize/visualize.

1. The outward-facing wall (that would butt up against where the stairs to the porch area) was wet in both corners. More wet than I would expect it to be, but maybe I'm wrong here. I don't know if that water in the plastic "seeped" there, or if it ran there from the larger problem, read next item. :)

2. (This is the one that scares us). The short wall shared with the garage - apparently the porch was poured after that was sided and no one cut back the siding, so it extends between the porch and foundation and "sticks out" of the ceiling in the floating area. We never noticed this (there is no light in that part of the floated porch), nor did the builder/inspectors. And umm, ignore the "?" in that picture. We weren't sure it was siging at the time, but it definitely is.

3. The wall just outside the floating porch (to the right of the front door) had a small trail of water running down it. It had stopped running before we could figure out what was going on and grab our camera.

There is some kind of plastic sheeting "stuck" to the ceiling in the floated area. We were told it was from the pour and could stay/go, wouldn't matter. But a lot of water had collected between it and the concrete, so now we're wondering if it's some kind of moisture barrier (we haven't touched it, but it is hanging down in some areas...) BTW, this is the second "wet corner", adjacent from the one in the first pic.

Amd a picture showing the three things I've itemized above:

This is a new custom construction completed fall of last year, so it's the house's first exposure to real weather - and our first exposure to the house in weather. We are well within a comprehensive 1 year warranty from the builder, and we have a meeting set up with them Wed to discuss these issues. I'm hoping to get more informed about what we should be requesting, what they should be offering, what we should avoid, etc. When we called them about this they suggested caulking the perimiter inside & outside (this is without seeing the pictures yet and just going off our "we think it's" descriptions). To me caulking a place where siding is breaking the integrity of the concrete-to-concrete joint is like putting a weak bandaid over a perpetually open wound. So what kind of fix do we need to pursue? What is it going to take to restore this to "should have been in the first place" status?

Thank you so much in advance for any insight you can provide...


Follow-Up Postings:

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RE: Floating/suspended porch - concrete/joining issues (pics)

I'm not sure what you mean by a "floating porch". I think you're saying that you have an open porch area at grade and that your basement extends under the porch area. The porch has a concrete floor which acts as the "ceiling" of the basement area below. You had snow accumulation on the open porch and as the snow is melting it's leaking into the basement below. the plastic is a vapor barrier installed on the underside of the porch slab. At at least one location there is siding protruding from the joint between the foundation wall and edge of the porch slab, indicating that the house was sided prior to pouring the porch slab and there is likely no connection between the slab edge and the inside wall of the foundation. (if so, then what supports the edge of the slab?). If the slab is properly supported by some other means then a cold joint between the two concrete elements (fouundation and slab) is no big deal. Caulking/sealing a leaking joint is a temporary solution at best.

The joint should be selaed with a membrane or other waterproofing system that will direct the moisture to the outside and prevent it from getting into the joint.

"Flooded" is a relative term. Was there in fact standing water in the basement area or are you referring to the droplets shown in your picture as a "flood"?

Hope this helps.


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RE: Floating/suspended porch - concrete/joining issues (pics)

Was there a snow build up on the porch and it melted or is the porch pitched to the house and water is draining toward the house? And as was previously stated what is holding up the porch where the siding is showing? What I would feel comfortable with would be to remove a couple rows of siding, install flashing and hopefully apply a overlay of a concrete bonding mixture and make sure the porch is pitched outward. Any caulking solution is temporary. You have a new house and your issues should remedied correctly and permanently.


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RE: Floating/suspended porch - concrete/joining issues (pics)

Hi, and thanks for the responses!! I've only heard of areas like this called suspended or floated. But I think we're talking about the same thing. The underside of the porch is the ceiling of the room. In the original floorplan this area was unexcavated. We wanted it to be usable sq.ft. and the order was for a "floating porch". More generically, an area that would otherwise be dirt has been dug out and added into the foundation. :)

I will do my best to address your questions. Please bear with me. This is not even a remote cousin to my area of expertise. :)

sdello - Cold joint sounds like what I was looking for. I didn't know the solution I was after, but I didn't consider caulking a solution. That is exactly the kind of help I needed, and thank you. There was never just standing water, because the water was making its way out of that area and to a floor drain. But what was there was about an inch deep, and managed to completely saturate 5 moving boxes we had sitting on the floor down there. It was definitely not just some drips from the plastic - and most of the water was definitely coming directly off the siding (we could see it). If that plastic is a moisture barrier, it is not attached to the concrete in all places. There are some places where it has "peeled" down and you can see/touch bare concrete.

don92 - Yes, there was a snow build up on the porch that was melting. More specifically, right at that angle where the short wall meets the porch floor. The porch is pitched to the front of the house, but the path of least resistance seemed to be straight down rather than out.

I would have to talk with the concrete company/builder to find out the specifics of how the porch is attached. I will start on that. :)

I pulled some pictures from the construction that might (or might not) help show what was done. I also added some that show the "floating" area specifically - I don't know if there's anything in its construction that will show how the porch is supported. I will also ask our builder and can share the response here.

Here is the album: Porch construction. I have MUCH larger versions of these files if more detail would help.

Thank you again very much, and I'll do whatever I can to get any information that helps you help me. :)


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RE: Floating/suspended porch - concrete/joining issues (pics)

the definition of a "floating" porch is that it is independednt of the main house structure. I'm not convinced this is 100% true in your case as the house and the proch share a foundation.

Anyway, from your limited pictures I gather that the porch slab was poured on top of the foundation perimeter not shared with the house. I'm still unclear on the support where the door and window are, but clearly there is no support at this short wall next to the garage. I suspect the slab was designed to span the short direction of the "hall" so no support at the end wouldn't be a concern.

I believe that the fact that sheathing runs through the joint here is the main reason for your water issue. As don said one solution is to be put flashing at the top surface of the joint turned up under the sheathing to direct water running down the sidiing on top of the porch slab and prevent it from going into the joint.

You should get clarification/understand the connection of the porch slab to the house because if that has a similar butt joint with no flashing, then water can get to the underside of the slab there too.

On the perimeter I believe the slab is on top of the foundation wall and continues to the outside edge. As long the porch slab slopes away from the house there should not be any water intrusion issue there.

Hope that helps, but remember any advice you get from the interenet is only worth what you paid for it.

Good luck.


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RE: Floating/suspended porch - concrete/joining issues (pics)

Thanks again. Our builder came out and looked at it and kept alluding to a silicone sealant solution. I don't know the name of the product but it was referred to as "nasty stuff" :) I replied with a synopsis of the information here, suggesting that maybe that could be done in addition to your suggestions. Builder is going to be out Monday with subs to look.

Thanks again for the help.


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