Where to find a flashing detail for patio to house connection?
The architectural plans show a patio area which is surrounded on 3 sides by the house – almost like a courtyard. The homeowner would like a no step entry into the house.
I believe this is in conflict with the foundation and framing plans which call for a framed floor system on top of the foundation wall. Code requires 6″ of clearance from finished grade to framing/exterior cladding. If we keep the top of the patio 6 inches below the top of the concrete foundation wall, we will have 18 or 19 inches to the top of the subfloor.
Is there an accepted flashing system that would protect the floor rim joist from moisture and termite intrusion if we build up the exterior grade?
Or an acceptable foundation detail that would recess the floor joists in the foundation wall?
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Replies
Beth,
If you have architectural plans, I suppose you could ask the architect.
Here's my opinion: either install a patio at least 8 inches lower than the lowest wooden components of the house, or install an above-grade deck.
Or you Architect or designer could do an extended concrete wall on the three sides with a reversed brick ledge (ledge inside, on the basement side). It'll allow to set your sill plate, trusses and flooring flush with the top of the concrete ledge, and then build your exterior wall on top of the concrete wall extention.
Here is a quick detail for you. I use it often when no-step entry is required for Universal Design or Handicap entry.
Beth, you don't mention your location. If your climate is mostly dry Armando's detail will work (though I'd be concerned about the thermal bridge). If your climate has significant rainfall you're likely to have problems. Our general strategy is to use a plinth course of masonry (brick, stone, stucco on CMU) at least 18" high above the patio to protect against back splash from overflowing gutters, over a peel and stick flashing on the sheathing extending 8" below grade level. The brick shelf is on the outside of the foundation wall to carry the plinth course.
And of course make sure the patio is drained properly away from the house walls. If you're in snow country your thresholds will still be vulnerable to ponding/flooding if the patio is not kept clear of snow/ice dams at the thaw.
Correction: I should have said to install peel and stick flashing extending 8" below the bottom of the wood framing elements, not 8" below grade level.
All of these comments have been helpful. Thanks esp for the detail! The project site is in a mixed climate in KY. The patio will be completely protected by a roof which will help to control gross water issues, but KY is in a moderate termite zone, so a big concern is for the long term safeguard against termite entry.
A typically built home with an exposed entry cannot have a no step entry from a same level patio into the home that does not leak. The interface of foundation, patio, framing, door frame, door panel, threshold, sweep and trim is far too complex to be water proofed by even the best labor. There is no drainage (non-flat) plane. If the customer demands "no step", excavate a couple of feet and pour a slab with gravity drainage. then follow the typical construction of a terrace on a roof. This is what you really have. there are thousands of hotels with "solid" roof terraces without step down. A water resistant exposed no step opening is not cheap. Better yet, explain this to the homeowner and end up with a properly sloped patio with a small step. Think about it. A sill pan or flashing MUST have some place to drain to. Water goes most easily down hill.