[71Whaler]

I have a Cape Cod built in 1935 which I would like to add a 10x10 laundry room addition to. The main area of the house is on a crawl space however the current laundry room is off of the kitchen and is on a slab. The current laundry room is 10'x7'. (see attachment). So you step down from the kitchen into the laundry room and then out the back door to get outside. What I would like to do is add a 10x10 addition and make this a laundry room and then extend the kitchen into the old laundry room by opening the wall and installing a header across and raising the floor to meet that of the house in both the old laundry area and new addition. I plan on getting all needed permits, inspections. My questions:

1) Can I under building code, raise the floor in the old laundry room to the house floor height? This would be over the slab and the distance between the floor joists and slab would be less then 18".

2) For the foundation of the addition we were going to pour concrete footers below the frost line and leave bare ground between however to match the floor of the main house the distance between the joists and ground would less then 18". Is this up to code or would we need to excavate dirt to bring it to 18". Alternatively could we have a slab and have less then 18" between joists and slab?

I asking these questions as I was planning on going to the city this week and wanted to make sure what I plan is feasible under code.

Thanks.

 

[oh'mike]

Sorry,I pulled up the attachment and found nothing useful--perhaps post something here?

 

[AndyGump]

This is what he posted.

Andy.

 

[AndyGump]

I think the minimum for crawl space access is 18" by IRC, at least it is here in CA. by the CBC. That is from earth to the bottom of a non pressure treated FJ.

Andy.

 

[71Whaler]

Thanks. Does it matter if there is a concrete slab instead of bare ground? For example in the current laundry area there is a slab and my plan was just to run joists across, then subfloor, to raise the floor to the same level as the kitchen.

 

[jcrack_corn]

you need to call your local framing/building inspector (depending on how big a city you live in there may be specific guys).

you likely have lots of options...you can possibly just build up from the slab as you mention, you can possibly core and rod the slab and pour new foundation walls on the perimeter to support the new structure, you can possibly box, core and rod, the slab and pour it to final height (leaving you with a REALLY big thick solid foundation).

you can possibly use steel instead of wood joists to meet your minimum crawlspace guidlines.

your local inspector should be happy to tell you what they will allow/pass.

 

[71Whaler]

Thanks. I am planning on going down to the city office next week.

 

[Gary in WA]

The 18" is against decay. As mentioned, check locally. I've done two additions/conversions joisting over a slab---- 12" was required, same distance as clearance to a beam. Try to wire and insulate before covering if they let you drop lower.....may need an inspection too; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_3_sec017.htm

Gary

 

[71Whaler]

Thanks Gary. I just wanted to get an idea of whether I was in the ballpark with what I was planning before i went and spoke to the permit/code office.

 

[71Whaler]

Met with the Planning Office today and they were very helpful. Provided me with a handout which showed the different plans that I need to draw and made suggestions on the ones I already had. They also said that I could keep bare ground underneath (with vapor barrier) and if the distance is less then 18" from joist to ground then I just need to use pressure treated wood for the joists. Also said that when I raise the floor over the slab area, that I will still need to put a vapor barrier over the concrete slab. When I start the project (hopefully in June) I will post pictures as I proceed. Thanks everyone for your input.