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Builder Patio Error - Now What?

Posted by drjoann (My Page) on
Sun, Jun 27, 10 at 10:15

We're doing a new build of a custom home in the Greenville, SC. There a patio accessed by the lower level rec room that is under an Ipe deck accessed from the great room, above it. The patio was supposed to have concrete pavers & we have a budget for those. Because of the terrain, a stem wall was needed at the perimeter of the patio.

Unfortunately, when they poured the stem wall, is wasn't really a wall & now we have a concrete patio underneath our still to be built deck. Even worse, it is a gray concrete patio when all of our other flatwork is supposed to be colored. We can't do the pavers without removing the concrete & we don't want the concrete, as is, so what are our options?

Here is a picture of the area taken by our neighbor whose camera has the wrong time/date. (We are doing a remote build while living in TX).

Back of House 06-26-10

I guess one option is to accept it & just try to "tart" it up with a stain. However, we've been told that to look good, the staining process needs to be done when the concrete goes in. It has also been suggested that we look at concrete resurfacing, but some others have said those look good from a distance but not up close. DH is looking at thin pavers where the perimeter gets locked down and the rest are set in sand.

We thought of using the same TN flagstone that will be on the front terrace. I got very strong advice from the new home forum to have the builder rip it out & do it right because flagstone (or anything else) sitting on an impermeable surface and the covered with a deck could "sweat, become slick, grow mold".

We would really appreciate any suggestions you might have. We certainly don't want it as it currently is and we don't want to be buying into future problems with alternative solutions. If the builder really needs to tear it out, we will have him do it, but we want to spend "silver bullets" judiciously.

Thanks for the help - Jo Ann

Thanks for your suggestions - Jo Ann


Follow-Up Postings:

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RE: Builder Patio Error - Now What?

I would worry more about mold issues. Tyvek vapor barrier? How are those windows flashed? If they used Tyvek tape you are dealing with really bad builders. But seriously, Tyvek is a main cause of mold issus, especially in a humid climate with high the dew points.

Forget about the concrete patio screw-up. There are way bigger problems you don't even know about. You need to speak with the building inspector. Hopefully he isn't friends with the builder and actually knows a little about construction.


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RE: Builder Patio Error - Now What?

Is there something particularly wrong with the Tyvek brand as a moisture barrier? The link below is from the Nichiha site and the installation guide for the Sierra Premium shakes shows using a moisture barrier. Tyvek is commonly used in the region, including $1 million plus homes.

I'm not sure about the windows, but they are aluminum clad wood. What questions should we be asking our builder?

Thanks - Jo Ann

Here is a link that might be useful: Nichiha Sierra Premium Shake Installation Guide


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RE: Builder Patio Error - Now What?

quote" We thought of using the same TN flagstone that will be on the front terrace. I got very strong advice from the new home forum to have the builder rip it out & do it right because flagstone (or anything else) sitting on an impermeable surface and the covered with a deck could "sweat, become slick, grow mold". "quote

Only you can decide if you feel that having the builder rip it out is the way to go. I'd say that if you have 4" plus under your door threshold to the concrete you can use thinsetting cement and lay your patio pavers right over the concrete. Most patio pavers are 2" tall and thinset goes on just as the name implies, thin. I would not sand set them on the existing deck
If you don't have much clearance under the door you can use a 1" flagstone like the Tennessee you mentioned. It should be cut and cemented down to the concrete.
I used some Tennessee flagstone on several pools I built years ago, I believe it was called Crab Orchard multi-color.
It was beautiful, but my local rockyard quit buying from that quarry and stopped carrying it in his stock.
On the staining aspect I would bet that the finish on the new concrete will not be receptive, we make the new concrete as flat and smooth as possible by working the fat and polishing as the concrete sets up when we do a stained and scored finish. I'll bet your finish is lightly broomed, these broom strokes will show terribly after staining, I'd call it the last option of all.
If you need something very thin you can look at an acrylic knockdown product such as Sundek.

I do agree with aidan on the Tyvec tape issue, you must have window flashing above the window and out 3 1/2" to the bottom edge of the overhead window trim board.
I disagree about Tyvec being a poor moisture barrier, I've seen it used all the time in SE Texas near the Gulf Coast on homes of all price ranges and have heard no negative reports about it when it is properly taped at the seams.
However, with my bad eyes looking at the computer picture screen I can't tell if they used any tape at all on your seams or around the windows. You should really ask the neighbor to get you some close up shots of the windows and seams.

BTW, I think your siding is AWESOME!!!

See ya,
Kelly


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RE: Builder Patio Error - Now What?

Tyvek is too airtight to let the walls breathe. Vapor barriers are essential, but it has to be done right. I know there are lots of newer dwellings that have to be completely rebuilt from mold damage, and Tyvek is the common link.

Water will get into your walls inevitably. If not through the improperly flashed windows, it will from condensation. Asphalt impregnated paper does a good job of keeping the moisture at equilibrium. It is more breatheable than tyvek, but the same effectiveness as a vapor barrier. (neither one will soak through if saturated with water). If tyvek is so great, why aren't roofers using it?

The studies about mold contamination often point to Tyvek as the culprit. However, I am not 100% convinced that the Tyvek textile is the only problem. I believe it is commonly installed totally wrong. The tape is what I believe causes many problems. Builders often substitute the tape for door and window flashing. Standard vapor barriers simply overlap courses which allows air flow. Tape the horizontal seams and you eliminate it.

Add double glazed windows, high R-value insulation, and an energy efficient HVAC system, your house has become an airtight vessel. Unless you diligently open and close windows year-round, the fresh air exchange will be inadequate to prevent toxicity.


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RE: Builder Patio Error - Now What?

joanne,

First, the Tyvek. and these comments are somewhat directed towards aidan's last post:

"Tyvek is too airtight to let the walls breathe. Vapor barriers are essential, but it has to be done right. " Tyvek has a perm rating of 58. It is not a vapor barrier, not even close. A vapor barrier has a perm rating of less than 1. The micro-pore structure of Tyvek allows moisture vapor to pass through it, but not liquid moisture. Now problems with Tyvek can occur when siding like unpainted cedar or redwood siding is in direct contact with the Tyvek. Extractants in those woods can mess up the micro-pore structure of the Tyvek membrane. But these shingles are fiber-cement, so no worries there.

If cedar or redwood is to be used over Tyvek the wood can be backprimed or installed over a rain screen to isolate the wood from the housewrap.

"Asphalt impregnated paper...is more breatheable than tyvek, but the same effectiveness as a vapor barrier." Tar paper has a moving perm rating, generally from about 5 when it is dry to about 60 when the relative humidity is in the 95% range. So when tar paper is wet or vapor saturated is has a perm rating (60) similar to Tyvek (58). When tar paper is dry (perm rating of 5) is resists the passage of moisture vapor much more than Tyvek (perm rating of 58).

As to either being an air barrier, Tyvek is a more effective air infiltration barrier, especially if the seams are taped with Tyvek tape. Tar paper, due to more seams and it's structure, allows more air to pass through than Tyvek.

One thing to be careful of with tar paper or felt is that most of the ASTM testing done on felt was with 15#, or "15 pound" felt. This was the "old" felt that was made from wood pulp and that had 15 pounds of asphalt impregnated into each 100 square feet of paper. The "new" felt is usually labeled #15, or "Number 15" felt, it's made of recycled paper and cardboard, and only has half the amount of asphalt, roughly 8 pounds, per 100 square feet of material. And it's usually not stapled with any ASTM certification. If it;s worth anything, todays #30 felt has abour 15 pounds of asphalt or tar product per 100 square feet. So "#30 felt" could actually be called "15-pound felt." Oh, the humanity!

So what am I, a tar paper hater? Not at all. For quite a few applications I prefer it to Tyvek. I'm just trying to clarify a few things.

As to flashing, in a perfect world there would be a "peel and stick" membrane used to flash the window/door openings in addition to the Tyvek wrapping the opening.

It's too difficult for me to see how your windows are flashed. Flashing can depend on the construction of the windows...are they installed with a nailing flange and then trimmed out, or did they come with the flat casing already attached?

Personally Id like to see peel and stick membrane (like Protecto-Wrap) used on the window pan as well as the window jambs and header. How it is flashed depends on the construction of the window.

As to the pavers versus concrete, hopefully they sloped that concrete slab away from the house. If it is sloped, you can use most any stone over it. If you want to stick with the paver look and minimize the elevation gain, there are "thin pavers" or "overlay pavers" that are bout 1" thick and they are just for this purpose...getting the paver look over a concrete slab.


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