Is the stucco on a wood frame house allowed to extend down into the ground?
Saturday, August 17, 2019
No, the stucco is not allowed to extend into the ground on a wood frame house. "On wood-frame construction with an on-grade floor slab system, exterior plaster shall be applied to cover, but not extend below, lath, paper and screed,” according to both the International Residential Code (IRC R703.7.2) and the Residential Edition of the Florida Building Code.
It used to be acceptable and we still see it on some homes built in the 1980s and earlier. But when stucco extends into the ground on a frame home it creates two problems:
1) No termite inspection area - Many pest control companies in our area will not issue a termite bond (insure the house against subterranenan termite infestation) because it is possible for termites to crawl through any tiny gaps where the stucco has not bonded to the concrete, below the wood base plate of the wal, and then enter the wall framing and start doing structural damage while undetected. Remember, termites are very tiny. Two will fit on the head of a match.
When the stucco stops above the ground, there is an exposed surface the termites must build mud-tubes to cross and their presence becomes observable. The building codes require a minimum of four inches. To learn more about why this “no man’s land” that termites must cross to get access to the wood in a house makes them so vulnerable, see our blog post How do termites infest a house and remain hidden while doing major damage?
2) No route for any water that enters the wall to drain out - Stucco always cracks a little over time. You may have to look closely to observe it, but the tiny cracks are there unless they have been recently repaired. Rain water seeps in thru these cracks, gets trapped in the wall, and rots the wood wall sheathing and faming if there is a way out at the bottom. So the International Residential Code (IRC) and the Residential Edition of the Florida Building Code both require a weep screed at the bottom of the stucco.
To learn more about weep screeds, along with the other details necessary for a well-built stucco-over-wood-frame wall, see our blog post Why is my stucco cracking? Incidentally, the gap and weep screed are not necessary for stucco over concrete block.
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Here’s links to some of our other blog posts about STUCCO:
Weep screed diagram - CodeCheck
How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactued and modular homes
for Links to Collections
of Blog Posts