Cautions for doing decks close to grade - Contractor Talk - Professional Construction and Remodeling Forum

UpNorth · 09-29-2009, 09:12 AM

In a house design I am working on, an entry porch and a screened porch are at opposite sides of a small house, both completely under roof.

In evaluating the options for the floor structures of these spaces, I am wondering what cautions might need to be observed if we do the floors as wood decks supported with concrete piers down to below frostline.

The joists and beams for these decks will sit only a couple inches off grade. What is done to ensure long life of the structure?

**genecarp** · 09-29-2009, 10:01 AM

What specifically are your concerns? Obviously no wood to earth contact, footings below frostline/check...G

**framerman** · 09-29-2009, 11:07 AM

That I believe will be a code question only your local CEO will be able to tell you. I'm thinking under 12" you need to take different precautions than usual.

JonM · 09-29-2009, 11:23 AM

IRC R319...joists closer then 18" and beams closer then 12" have to be PT

DavidC · 09-29-2009, 11:23 AM

Drainage. You don't want water to sit under there. If you don't have natural drainage consider excavating, landscape cloth and gravel to expedite run off and control weed growth.

Good Luck
Dave

Greg Di · 09-29-2009, 11:58 AM

Quote:

Originally Posted by DavidC

Drainage. You don't want water to sit under there. If you don't have natural drainage consider excavating, landscape cloth and gravel to expedite run off and control weed growth.

Good Luck
Dave

That's really all you have to do. You'll have minimal water UNDER the deck if there's a roof over it, but even so, control the water and drainage and it's half the battle.

deckman22 · 09-29-2009, 05:14 PM

What they said about drainage & cross ventilation. Sloped ground & air flow over that ground = no promblems. Gound contact TP too, not the cheapo stuff @ home cheapo.