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.