Can I add a basement?

Old 01-10-05, 11:10 AM
Visiting Guest
Posts: n/a
Can I add a basement?

Im a pretty handy guy, me and my wife have been remodeling the house
room by room for a year now. Having lots of fun and the house is really
starting to look good. We live in a 1200sqft townhome with shared walls
on either side. We were thinking it would be so great to be able to dig out
a basement under the house, if possible.

Right now we have a 25'x25' , 4 foot high crawlspace under the house, the
floor of the crawlspace is ruff poured concrete (unsure of the depth). There
are also 4 pillars evenly spaced to support the house. The foundation does
form a wall around the outside walls of the townhome.

Would it be possible to dig a basement? I have read the deed & homeowners
association info and I do indeed own the townhome as well as the ground
underneath it. And nothing specifies that I can not dig deeper. So I think
legally I can do it, but I am not sure about the logistics of supporting the
foundation, breaking up the existing concrete, dirt removal, etc.

Ideally I would like to work with a local licensed contractor. I can do alot of
manual labor, but I would like someone who really knows there stuff to tell
me what to do. And I will definitely need permits, but before I started
calling around I thought I would ask here to see if they will laugh at my
idea of a full basement under a townhome. I am in the Bay Area, CA.

Old 01-10-05, 03:04 PM
Visiting Guest
Posts: n/a
Having been down this road before, I can honestly say, don't do it. The expense for you is not going to be worth it. I did it because i had to do it. The main problem with your scenario is the fact that you have shared walls. Because this creates a liability concerning the health and safety of your neighbours, as well as their property, i highly doubt a permit would be granted. I also beleive that any decent foundation specialist would not want to tackle this job because of those liabilities. If they do, it's going to cost you large.

With that said, if you still want to do it, and cost is no object, here what will likely happen. You'll need to excavate below the footings, then underpin them. An underpinning specialist would definatly be needed here. To do the excavating, you will need to get a bobcat in there. My little Bobcat is 6'10" tall with the cab on. You'd need to break a hole in the wall to get it in. The excavating will need to be done in stages so you can maintain the houses structure when you move the posts around. You will need to dig down to pour new footings for these posts. Where is that dirtpile that will be the size of your house going to go? Can a dumptruck get into your back yard? Once the excavating is done, and the footings underpinned, you will need to do plumbing, weeping, waterproofing, etc. Don't forget that after this is done, your basement will be the lowest point on the row.....water flows downhill.

This is not a diy'er type of job.
Old 01-11-05, 08:27 AM
Visiting Guest
Posts: n/a
Yes, it would definitely be a large undertaking that I would need professional
help with. But, a 500sqft finished basement would add over $100k to the
value of the home. So I figure it is at least worth researching.

Can anyone suggest a specialist in California? I figure the first step is to
inspect the area, and if possible, make a game plan to take to the city.

Old 01-11-05, 01:11 PM
Visiting Guest
Posts: n/a
Whatever you do, make sure the GC brings in an underpinning specialist.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: