Home>Discussions>EXTERIORS>Crawl space entrance is too small - can I enlarge it?
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Crawl space entrance is too small - can I enlarge it?

Our current crawlspace entrance is under an addition to our house (built in 1942) and is much smaller than a "standard" size entrance. I need to measure its exact dimensions but I think it's about 12" H x 24" W. The addition was put on about 10 years ago by prior owners. The original crawlspace entrance is a larger, "standard" size, maybe 32" H x 32" W but is now only accessible through the crawlspace under addition. We want to expand the current crawlspace entrance under the addition so that we can get under the house more easily to install and replace some insulation and fix some ducting and plumbing. But from calling around to some foundation repair companies in our area, they all seem to act like this sort of problem is new to them and they don't know of anyone qualified to do such work. Anyone have advice on how to proceed here?

I should add that the crawlspace height under the original house is about 3', but under the addition it is only about 18". We also plan to add a good, sealable access door to the crawlspace to replace the wooden box insert that's covering it right now.

A. Spruce
Re: Crawl space entrance is too small - can I enlarge it?

Not sure why you're getting surprised responses from tradesmen, as this shouldn't be too big a deal. A 24" wide opening is pretty spacious, so this should just be a matter of adding height to the opening. You can cut the bottom of the opening down to the sill plate (board on top of the foundation. If the sill plate is anchored on either side of the opening, then you can remove the sill plate too if you want. To raise the opening, you do not want to cut anything structural, unless you've reinforced the structure to withstand alteration. Having said that, you can cut siding up to the bottom of the structural support.

Before you start cutting anything, however, I recommend that you do some careful inspection and measuring, then see what kind of access covers are available so that you can cut the opening accordingly. If you are going to make a custom cover, then you can do whatever you want.

This can't be stressed enough, DO NOT cut any structural components without reinforcing the area properly beforehand.

Re: Crawl space entrance is too small - can I enlarge it?

I have a question: Was the addition permitted?

No inspector would approve such a small (low) access.

Re: Crawl space entrance is too small - can I enlarge it?

How about putting a new access door in the original house that is large enough.

Re: Crawl space entrance is too small - can I enlarge it?

Also note that Brickwork can be structural too. One crawlspace door I did had to have 4 rows of brick above to meet structural needs for the building above, even with a lintel. There were other ways around this but the customer was OK with this as we still had a lot of height, and this was the most economical approach.

I prefer large access to crawlspaces, both for future service work and so that the customer can use the area for storage. One of my faves is to install an exterior-grade 'smurf door', complete with weatherstripping, threshold and deadbolt. It makes for an easy install, good security and access, and a great look- but it does increase costs. IMHO it's much nicer than your usual site-built plywood faced door, and by the time you factor in the labor for building the usual plywood one, it's not that much more to do the pre-hung.


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