New Addition - Crawl Space Foundation

by Cory
(Sammamish, WA)

Hi Tonga,

I'm in the planning stages of expanding my home to accommodate a great room that will have a cathedral ceiling. My home has a crawl space foundation that is vented. I was wondering if the new crawlspace has to be the same depth as the old crawlspace.
Also, do you find it's easier to create a new crawl space access door for the addition or would it be better to cut through the old crawl space wall and extend access into the new crawl space? Finally, how does one determine where to cut the access holes into the existing foundation to extend HVAC, gas, and electricity, water, and sewer?

Thanks so much. I really like your website....there is a lot of good information.

Cory

Hi Cory,

Thanks for visiting and your kind words

Q: “I was wondering if the new crawlspace has to be the same depth as the old crawlspace.”

A: It does not have to be the same depth, but from cost and ease of construction it will be best for the new crawlspace to be at the same depth or shallower. If the new crawlspace is lower than the existing, you will be required to build some type of shoring to hold the existing house in place during and after construction. The cost of such shoring varies greatly depending on the depth.

Q: “Do you find it's easier to create a new crawl space access door for the addition or would it be better to cut through the old crawl space wall and extend access into the new crawl space?”

A: It cost $200 to $300 to saw cut crawl space wall to create access – it may cost more or less where you are. In construction that cost is very small to be the determining factor in the decision for the location of the access door. I would pick the most convenient location for your access door and go for it.

Q: “Finally, how does one determine where to cut the access holes into the existing foundation to extend HVAC, gas, and electricity, water, and sewer?”

A: The locations of HVAC, gas, electricity, water, and sewer lines at your new addition will be dictated by the layout of the same at your existing house. Normally the contractors that will be hired to do these work, they will be the expert that will provide you the best advice. I would get their input during the planning stage and throughout construction.

Hope this helps
Tonga