Hole In Foundation Or Floor? - Building & Construction - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Like Tree2Likes
  • 1 Post By joed
  • 1 Post By bob22
Reply
 
Thread Tools
Display Modes
Old 08-06-2019, 02:51 PM   #1
Member
 
Join Date: May 2008
Location: Near Philly
Posts: 2,801
Rewards Points: 2,516
Default

Hole in foundation or floor?


The prior owner of my son's home added three additions to it.
One addition has about a 3-4' high crawlspace under it but no access from outside or from adjacent crawl spaces from other additions of the house.

Someday he will likely need to get under the floor for plumbing or gas work (wants a gas dryer for example).

I assume it'd be easier to cut an access hatch into the floor (currently carpeted) than cut out a 32-36" wide section of an adjoining crawl space wall (cinder block)?

If the cinder block is the way, I presume a lintel of some sort would be needed?

Does a mason do this job or a carpenter?
Thanks!
bob22 is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-06-2019, 04:25 PM   #2
Super Moderator
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 19,639
Rewards Points: 30,600
Blog Entries: 11
Default

Re: Hole in foundation or floor?


Concrete block is easy to cut through as compared to solid concrete. I think that is the way I would go.
If a lintel is needed depends on if you are cutting into supporting wall. If the joists run parallel to the wall then less support is needed.
Msradell likes this.
joed is online now   Reply With Quote
The Following User Says Thank You to joed For This Useful Post:
prazzz (08-07-2019)
Sponsored Links
Advertisement
 
Old 08-06-2019, 04:54 PM   #3
retired framer
 
Join Date: Jun 2017
Location: Fraser Valley BC Canada
Posts: 31,360
Rewards Points: 6,378
Default

Re: Hole in foundation or floor?


With additions, it might take some figuring to know what all the loads are.

I would go for just wide enough to do the needed work and ignore min. access rules.
If the joist are going in the same direction, you might just double up the joist to make a header over the door, we do that for windows all the time.
__________________
Do not use flat bottom gables with scissor trusses.
Nealtw is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-07-2019, 09:12 AM   #4
Member
 
Join Date: May 2008
Location: Near Philly
Posts: 2,801
Rewards Points: 2,516
Default

Re: Hole in foundation or floor?


Thanks; I think both access walls are supporting so a lintel of some sort would be needed.
Nealtw likes this.
bob22 is online now   Reply With Quote
Old 08-07-2019, 01:30 PM   #5
Member
 
Join Date: Oct 2010
Posts: 5,427
Rewards Points: 558
Default

Re: Hole in foundation or floor?


Having an access from the main bsmt or space to the addition's space is always a good idea. It allows mix of conditioned air, example. Easier drying, etc. Addition crawl space can be insulated to make it into a conditioned air space and add to the insulation value of the house.
So it depends on which part of the addition you want to cut into. Main or addition foundation, your joists may be sitting on double sill plates. If double, you can cut the foundation 32" without any support. About 2 joist bays. Joists don't have to be directly over the cuts. Cuts can be wider than the joists by 1-2" also, on either side. Double plates can support that much. Double plate means no lumber joint in the middle. If one plate joins over the other, pick another area to make the opening. Then the middle joist can sit on the plates without further support. BSMT window openings are like this.
Not an engineer. Just what I've seen in single family houses up to 2 stories with a roof. Often, decks will be connected to this kind of foundation with window openings. Passes the inspection and no structural problems.

Last edited by carpdad; 08-07-2019 at 01:33 PM.
carpdad is offline   Reply With Quote
Old 08-07-2019, 04:54 PM   #6
Member
 
Join Date: May 2008
Location: Near Philly
Posts: 2,801
Rewards Points: 2,516
Default

Re: Hole in foundation or floor?


Unfortunately, the only sensible wall to cut into serves as the foundation for the original house footprint so it is holding a bunch of weight and would need a header of some sort.
bob22 is online now   Reply With Quote
Old 08-07-2019, 05:01 PM   #7
retired framer
 
Join Date: Jun 2017
Location: Fraser Valley BC Canada
Posts: 31,360
Rewards Points: 6,378
Default

Re: Hole in foundation or floor?


Quote:
Originally Posted by bob22 View Post
Unfortunately, the only sensible wall to cut into serves as the foundation for the original house footprint so it is holding a bunch of weight and would need a header of some sort.
Is the original house over the crawlspace in question or over the space you have access to?



Unless there are extreme loads you could just channel out for a header and quickly slide in the header and then make a whole below. Quickly as in, same morning, same afternoon.
__________________
Do not use flat bottom gables with scissor trusses.
Nealtw is online now   Reply With Quote
Old 08-09-2019, 12:39 AM   #8
Contractor/Engineer
 
Join Date: Nov 2018
Location: Desert Hot Springs, CA
Posts: 589
Rewards Points: 1,170
Default

Re: Hole in foundation or floor?


If there is a closet that's where I cut the floor, frame it properly and install a trap door. Hopefully there is some cross ventilation for that crawlspace.

I did this when putting up an addition years ago. I didn't dare go through the hand stacked boulders of the original foundation since they had 4 to 6" of concrete poured on the outside by a previous owner as reinforcement. (His wife hand dug the trench around the foundation down to the footings, the trench was wide enough that he could get in and build the forms for the concrete, which they hand mixed and poured. They also hand mixed and poured the floor. And, the fellow also made his own septic tank using old all-metal mattress box springs as rebar.) This was back when men were men, I guess.

I did install vents on each of the unattached three walls to allow air exchange in the crawlspace.
Domo is offline   Reply With Quote
Old 08-12-2019, 11:12 AM   #9
Member
 
Join Date: May 2008
Location: Near Philly
Posts: 2,801
Rewards Points: 2,516
Default

Re: Hole in foundation or floor?


Domo,
THanks for the thoughts.
No vents in the space although the radon contractor mistakenly drilled a 4" hole in one wall that connects to the original home crawl space.
Unfortunately, no closet in the space.
I just don't get why no one thought it unimportant when building the new addition to not add in a way of accessing the crawl space. Why have one if not?
bob22 is online now   Reply With Quote
Old 08-12-2019, 12:18 PM   #10
Member
 
Join Date: May 2015
Location: Mountlake Terrace, WA
Posts: 191
Rewards Points: 370
Default

Re: Hole in foundation or floor?


I recently replaced the sub floor in my house from particle board to plywood. I sealed all crawls from in the house up and rented a concrete chain saw and cut a hole in the foundation.

I will probably add a crawl in the very front bedroom of the house to just be able to access the furthest part of the house without crawling through the entire house.
If there there was not an addition to the house and a foundation wall in the middle of my home I would wouldn't add one there.

My opinion.
JPeters is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Top of Page | View New Posts