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grouted masonry footings

bill1952

SAWHORSE
Joined
Aug 12, 2021
Messages
2,061
Location
Clayton NY
R403.1 (2021 and I think 2018 at least) says "All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approved structural systems that shall be of sufficient design..."

What is a "fully grouted masonry foundation"? Looking at 2009 suggests a little more but frankly, I have been looking for a week or two to find out if I can use cmu for a footer or even what was intended by the code phrase. Does a 12" block below frost depth with an 8" stem wall, all fully grouted, qualify? (Seismic zone B) Thought about a 12" cmu bond beam at bottom course. Slab on grade unheated 1000 sf 1 storey no attic or storage above grade garage in 60 psf snow load country fwiw. Would like to avoid the work and costs of two concrete deliveries and forming footers, and dislike the idea of burying $1500+ of XPS, and trying to avoid the pole barn approach.
 
To use your terminology...CMU bond beam is what they are saying....The footing needs to be "solid" not necessarily "one piece"...if you can grout the wall and footing at the same time it should work...
 
Isn't it odd that this concept - a fully grouted masonry footing - is not pictured or referenced or hardly talked about anywhere on the internet? I have this notion in my memory that I once saw a cmu footer block marketed - maybe in late 1980's and pre internet - and can't find it now. Someone got a code change in for the product, which then never took off and was withdrawn from the market, but that language has stuck around.
 
Isn't it odd that this concept - a fully grouted masonry footing - is not pictured or referenced or hardly talked about anywhere on the internet? I have this notion in my memory that I once saw a cmu footer block marketed - maybe in late 1980's and pre internet - and can't find it now. Someone got a code change in for the product, which then never took off and was withdrawn from the market, but that language has stuck around.
I recently saw a "manufactured home" placed onto a CMU foundation. They used the standard cinderblocks you would expect to see in a CMU wall but filled the cavities with concrete/mortar to provide an adequate foundation, per plans. Isn't that what they mean by "fully grouted"? This particular one was done in two pours.
 
Joe, I don't know. NCMA didnt know. I think the answer is research into code changes, when it was added and when some language in earlier IRCs was removed.

It's a problem with prescriptive requirements.
 
18 & 19th century footings were usually made of bricks.

I remember a concrete footing block was made several years ago. If I remember correctly they were solid and had offsets on the edges where they butted, I guess to keep them in line. They would be laid dry on a few inches of gravel, then the foundation wall was laid with mortar on top of them. I'm guessing they didn't save enough money for anybody to use them.

The "fully grouted" probably applies only to regular hollow blocks used as footings. It doesn't appear to require the foundation wall to be grouted unless other code provisions (seismic, unbalanced fill above a certain height, etc.) require grouting.
 
Mortared stone walls may also be fully "grouted" - no voids without mortar. I wonder if that's too he origin. And the bricks I found examples of, though I suspect not done much today.

I agree on rest of wall not required to be grouted - that's simply my backup.

I appreciate everyone's comments. Perplexing code none to the less.
 
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