Wet-work And Wood

Rock Headed

Hi.

I have a customer who wants me to extend their existing patio. As seen in this photo

http://inlinethumb46.webshots.com/41...600x600Q85.jpg

This is flagstone, with concrete foundation, laid upon a bed of mortar.

Here is a quick pencil sketch that I just drew up so you guy could see what is being proposed. (I

http://inlinethumb23.webshots.com/40...600x600Q85.jpg



The new patio will extend to the door, and will replace the wooden steps that currently lead from that door. The door in question is part of an addition that was built a few years back.

My propblem is that, as you can see in the photo, the addition is built of wooden framing, with wood siding.

How do I butt concrete stone and mortar up to this wooden structure?

My first instinct is to remove part of the existing wall and replace with block work. Only a six foor wide and 2 feet high section of wall would need to be propped, removed and replaced. Customer doers not want to pay for that.

If somebody can help me engineer this in a way that the existing lumber can remain, without rotting, that would be awesome. Can I simply mount flashing, then go about me work as usual? I have some other, possibly rediculous ideas, but I would love to hear what you guys think.

Thanks.

tkle

As long as it doesn't rain or get humid it'll be fine.

stacker

i would just flash it and move on.

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neolitic

The old tried and true is sheet lead.

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tkle

Even with flashing my concern would be dry rot or the wood expanding and popping the masonry.

Rock Headed

Now the idea occurs to me. I think I could build a cinder block wall, leaving an inch gap between my block wall and the house. Then set my flagstone over hanging that wall and brigding most of the gap between the two, so it looks like the new patio is butted up against the house, but in actuallity it is not. Sometimes the answer is obvious.

neolitic

Just as bad as contact.
It still needs flashing.
You need to go up behind
the siding that will remain,
and well below any of the
wood framing.
Anything else is just
going to create problems.

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Tscarborough

A better option may be to deck that area.

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Rock Headed

I agree, Tscar, and that was my original suggestion to the customer. They don't like the look of decking, however.

Thank you everyone for responding, any additional thoughts on the subject would be appreciated.

I happen to really need this little job.

eoffmasonry

I would use peel and stick perm-a-barrier flashing were all masonry gets close to wood, not exposing the flashing outside the top or the wall sides. Then I would stop 1/2" short of butting the any wood solid with masonry and install a caulk joint with backer rod. I would design the walk with enough fall away from the door so that water ran off.

Perm-a-barrier membranes can be found at graceconstruction.com

The HO will need to keep the wood siding painted around outside of door area to maintain the siding from rot.

hope my ideas help...good luck

Rock Headed

Thanks, eoffo--your ideas are very similiar to what I was thinking. Here is a drawing of what I am planning now:

http://inlinethumb13.webshots.com/19...600x600Q85.jpg

Essentially, I plan to leave a 1" gap between the masonry wall that will exist to seperate my patio from the house. The flagstone itself will all but close that gap. I am looking into this permabarrier stuff, and may end up using it for my caulking and flashing needs. At the base of the house, a good 4" beneath the siding, along the foundation, will run a 4" trench drain.

Hopefully the drawing makes sense. Any additional thoughts? I am feeling confident, but if anyone wants to gives thumbs up or thumbs down on this concept, that'd be cool.