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Code requirement for vegetation clearance


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I've got someone challenging me on my recommendation to trim vegetation at least 6-12'' from a house wall (it's in contact right now). I've never been challenged on this, and honestly don't know where it is written in stone that a clearance is required. It's one of those no brainers that I have never sought out documentation before.

Can someone tell me whether it is written up in the IRC? I've probably read it a number of times and just breezed right over it. If it's not in the IRC, where can I find the requirement from a credible source?

Thanks,

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I don't think it's in the IRC and I don't ever remember seeing anything or anyone "requiring," it. However, I also recommend veg be cut away from the house. 12" minimum sounds good to me. Vegetation will trap moisture against the house and trapped moisture is always bad. Siding can be damaged, moisture can migrate into the house from this source, etc.

This paper about home moisture problems from Oregon State University may be a credible source for your recommendation:

http://extension.oregonstate.edu/catalo ... ec1437.pdf

Under, "Symptoms and solutions for home moisture problems" is Blocked exterior circulation.

The solution calls for cutting vegetation away from the house.

Check out pages 3 and 6.

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I don't think you'll find any documentation, Brandon. It's just a common-sense thing.

How often do people plant a sapling a foot or two away from a house so it won't look squirrely, but twenty years later, the roots are damaging the foundation?

If code books have ever addressed vegetation, I've missed it, too.

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Originally posted by Brandon Whitmore

I've got someone challenging me on my recommendation to trim vegetation at least 6-12'' from a house wall (it's in contact right now). I've never been challenged on this, and honestly don't know where it is written in stone that a clearance is required. It's one of those no brainers that I have never sought out documentation before.

Can someone tell me whether it is written up in the IRC? I've probably read it a number of times and just breezed right over it. If it's not in the IRC, where can I find the requirement from a credible source?

Thanks,

Just tell them that it is based on common sense and your past experiences of the damage you have seen from vegetation too close to the home.

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Years ago I use to say "cut back X inches away from the house", but it's really kind of silly as there is nothing no where official that says this plant, that bush, that tree branch needs to be so many inches from the building.

Today I just tell them "Cut back and maintainid="blue"> vegetation from contacting the building."

I guess unless there's such a thing as a jumping carpenter ant.

Chris, Oregon

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"Cut back and maintain vegetation from contacting the building."

I like that better than mine: Keep vegetation trimmed back at least 6-12" away from the structure.....

Mind if I steal err uhhh borrow yours?

I am not aware of jumping carpenter ants, but keeping it back will let the siding breathe / dry out better. I tell my clients that my house is 18" min. and they should shoot for that if not more.

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Just my humble opinion, but I don't think you want to go with a sentence that instructs people to "maintain vegetation from contacting..." Try "keep" instead of "maintain." Maybe change "vegetation" to "plants." And "structure" to "house."

At Walters suggestion I've been digesting Frank Luntz's book "Words that work".

I wonder though about the variation in the vernaculars between our various locals.

Since the first time Les scolded me on writing "hot water heater", I 've written "water heater", but on occasion when I have polled clients with such words they were more familiar with "hot water heater."

I think the same is true here with our local use of words like "vegetation" and "maintain".

Here if I say "plants", then people think I don't mean weeds, bushes and branchesid="blue">. On occasion in place of vegetation I'll say weeds, plants, bushes, branches, etc. Remember it rains here a lot and everything grows, thus we tend to use "vegetation". Perhaps in other parts of the country the only thing that pretty much grows is what you plant and therefore they tend to get called "plants".

The same with "maintain" vrs "keep". People here seem to respond differently to those words. "keep" is something that is optional whereas with "maintain" they tend to perk up and say to themselves "Oh, this is one of those housey things I have to remember to do periodically."

I lived on Long Island for a couple of years, and there was clearly a difference in vernacular. They were utterly confused when I told them I was going to get a "pop". Here in Oregon, the use of the word "soda" is a recent import.

Chris, Oregon

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Gosh Brian, if they're challenging you on that issue, they might be challenging you on everything.

How about incorporating the phrase "according to industry standards"? The entire inspection community agrees that it makes sense to keep bushes, shrubs, flowers, etc. trimmed back from the foundation and siding. Why do we need to rely on another authority? In this instance, I suggest we act as the authority based on our individual and collective experiences as inspectors.

I also make mention of keeping tree limbs trimmed back enough to discourage convenient access to roof and attic by animals, and to prevent damage to roof and siding.

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Hi Hank,

The strange thing is that almost any time someone challenges me on something, I have a reference to back it up with.........in this case I do not.

It's a no brainer on this one, which is why I have never had to pull up a code reference or any other source.

In my report's, I specifically write up "I recommend" so they understand that it is my recommendation from this inspector only, under certain circumstances such as this one.

They can't usually challenge me on much else in my reports, as I can back things up............

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Hi,

Vegetation touching a house is not just about moisture; it's also about wood-destroying insects that will use the vegetation to bridge any chemical barrier treatments. I first read the vegetation thing before I got into this gig when I was still in the army stationed at Ft. Carson in Colorado. I drove down to Pueblo to the US Government Printing Office Bookstore one afternoon to browse the shelves and while there found a copy of Subterranean Termites - Their Prevention and Control in Buildings which is authored by the USDA's Forest Service branch.

In the section that talks about inspecting for subs, there's this paragraph:

Wooden structures that are in areas where subterranean termites occur should be inspected periodically for evidence of active infestation regardless of previous preventative measures. If no preconstruction measures were employed, the structure should be inspected more frequently. The best physical barriers can be breached by termites, and under certain circumstances, even insecticides may be ineffective in stopping termites. The continuity of the chemical barrier may be broken, and maintenance or repair personnel may leave a termite-prone condition after working underneath or around the structure. Even the homeowner can inadvertently disturb the treated soil or place wood on the soil against or under the building. If not cautious, the homeowner may overlook vegetation that has grown over or through the chemical barriers, providing access for termites. Settlement cracks may occur in foundation walls or concrete slabs and allow termite entrance.
Under sanitation, it lists 7 control measures and the second of these states
2. Remove exterior wooden structures, such as trellises, that connect the ground with the woodwork of the building. Any wood remaining in contact with the soil should be treated with preservative.
If you're looking for this, it's known as Home and Garden Bulletin 64. I don't know when it was first published, but it was revised in 1989 and then slightly revised in February 1994.

ONE TEAM - ONE FIGHT!!!

Mike

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  • 2 weeks later...

Brandon:

If you really want to s-t-r-e-t-c-h the IRC:

R506.2 Site preparation. The area within the foundation

walls shall have all vegetation, top soil and foreign material

removed.

Removal of construction debris and foreign materials,

such as lumber formwork, stakes, tree stumps and

other vegetation, limits the attraction of termites, insects

and vermin. Top soil and soil vegetation should

also be removed because such top soil is generally

loosely compacted or so full of vegetation that soil settlement

will occur when the vegetation decays. For

concrete slabs placed on uncompacted fill or on large

quantities of foreign materials, differential settlement

may take place as a result of subsequent compaction

of the soil, which can result in cracking of the floor slab

and the interior wall/ceiling finishes.

This IRC 2006 commentary at least states the intention of the code to eliminate situations attractive to termites. You may be better off to refer to whatever literature is available from the entity in your state that licenses wood-destroying-insect inspectors. See page 7 of the attached document for an example.

Aaron

Download Attachment: icon_adobe.gif viewpdf_1021.pdf

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