# cut an opening in foundation



## Martydukes (Feb 12, 2008)

Hey guys. I need some help please. I've been tasked with cutting an opening in the foundation of a house. The house has a crawl space about 3 foot high at the highest point. 

The house has a poured foundation with bricks on the outside. 

My client wants to cut a new bigger opening in the taller section of the foundation so that he can have easier access to the crawl space. The original opening is very small and difficult to enter. 

What is the best way to cut a new whole in the foundation? 

One problem that I forsee is that the concrete saws that I can rent aren't big enough to make it through a layer of brick and the poured foundation. 

Any help?


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## Chris Johnson (Apr 19, 2007)

Rent a concrete chainsaw for the foundation portion, cut all the way up to the floor system, bridge the opening with a new header, this requires removing the rimboard, cutting back the joists to allow for the thicker header. Install a lintel for the brick in this area above the new opening. You may even want to remove the brick in the area and replace once complete.


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## neolitic (Apr 20, 2006)

Why would they hire a painter
to do this? :blink:
The foundation is a structural
part of the house you know.





I can't resist....
"Ask Sherwin Williams!"


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## Martydukes (Feb 12, 2008)

*any leads?*

Any leads on where to rent a concrete chain saw? I've called just about every rental house in town and no go.. 

Thanks
Marty


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## JonM (Nov 1, 2007)

Where are you?...Usually United Rental is the best bet for major rental equipment. 

http://www.ur.com/index.php/equipment/rental/browse/view/?category=Concrete+&+Masonry&id=2308


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## Martydukes (Feb 12, 2008)

*united rental*

I'm in Tulsa, 
I already called united rental and they said they don't carry it. Thanks for your help though.


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## gregj (Jul 31, 2006)

If all you can rent is a concrete saw you can make that work. First remove the brick carefully creating a slightly bigger opening than you need. Then cut the opening from the outside as deep as you can go. Then cut the opening from the inside to complete the cut. Proceed as Chris said above after determining the appropriate sized header.{Engineer or IRC table 502.5(1)}. Use the saved brick to finish the opening.

Oh, don't forget to brace as needed.


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## Chris Johnson (Apr 19, 2007)

If you're in Tulsa, find Joasis on here, I'm sure he can recommend the right place for you to find the concrete chainsaw. A regular concrete saw for what you are doing is tough and not as clean a finish...it can be done, but look for the easier way


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## 6stringmason (May 20, 2005)

I've used concrete chainsaws and they are pieces of junk.

You're much better off with a good german saw and doing like gregj said.

It will be MUCH faster and easier. You need to put a lot of pressure on those chainsaws in order for them to do anything. 

I rented one once and returned it an hour later. Never again...


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## Joasis (Mar 28, 2006)

I am surprised that United Rentals does not carry a concrete chainsaw, and I don't know anyone else that would carry one, except Tulsa Industrial Equipment Sales may have one they would rent, you can get their number from information. 

Now, since you list your trade as a painter, are you aware of any issues with opening up the foundation? Not really a permit issue, but you might be advised to call a city inspector, simply because if you do this, and something goes wrong, you are liable.


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## K2 (Jul 8, 2005)

You should probably know about tensile and compressive strengths. You'll probably cut some rebar and that could affect your tensile strength. In my world i would have an engineer design a repair for any cut i made in a foundation. But your world may be different.


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## dayspring (Mar 4, 2006)

Chris Johnson said:


> Rent a concrete chainsaw for the foundation portion, cut all the way up to the floor system, bridge the opening with a new header, this requires removing the rimboard, cutting back the joists to allow for the thicker header. Install a lintel for the brick in this area above the new opening. You may even want to remove the brick in the area and replace once complete.


 

IMO opinion Chris is on key:clap:


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## K2 (Jul 8, 2005)

dayspring said:


> IMO opinion Chris is on key:clap:


IMO that would work in many cases but not not all cases. In my area foundations have "beam" strenght and are often called "grade beams". Cutting a grade beam would be like cutting any other beam in the house and should be done with care... and an engineer. I learned this lesson the hard and expensive way. I... also don't think anyone should be giving advice on how to cut a foundation on these forums without knoing the particulars of that foundation and without a PE license for the state in question. That's my opinion anyway.


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## neolitic (Apr 20, 2006)

K2 said:


> IMO that would work in many cases but not not all cases. In my area foundations have "beam" strenght and are often called "grade beams". Cutting a grade beam would be like cutting any other beam in the house and should be done with care... and an engineer. I learned this lesson the hard and expensive way.


I think you are in one of the 
few locations in the country
where crawl walls are grade beams.
Most here are 3 or 4 courses 
of block.



K2 said:


> I... also don't think anyone should be giving advice on how to cut a foundation on these forums without knoing the particulars of that foundation and without a PE license for the state in question. That's my opinion anyway.


Never needed an engineer,
but there sure can be more
than knock a hole and
walk away.


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## K2 (Jul 8, 2005)

> I think you are in one of the
> few locations in the country
> where crawl walls are grade beams


.

I agree and i would not want any one here getting their engineering off a internet forum. And.. there are probably a few other places in the country where cookie cutter engineering might cause someone some trouble.


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## plazaman (Apr 17, 2005)

united rentals doesnt have a concrete saw? Find it hard to believe

i have a stihl demo saw for sale if you are interested.


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## Kgmz (Feb 9, 2007)

You are usually better off to hire a concrete cutting guy than do it yourself.

They will have the right equipment to do it very fast, and they know what they are doing. By the time you rent something and the time it will take you, it will probably be cheaper to hire it out.

You can do the prep work, removing brick etc. and get it ready for the cut guy.


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## Virg (Mar 18, 2008)

ive cut egress window openings into foundation walls and it has been accomplished with a "ring" saw. it cuts through the concrete great but you shouldnt just rent one and go at it. dont know your background in construction but i think you should disclose the fact that you dont know how to do it to the homeowners. anyway..... i tapcon a 2x4 to my cut line and let it be the guide. the carbon monoxide is where you should take caution especially in a crawl space. its a real nasty job. the professional cutters have a saw on a track and they are in and out


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## Hoven (Aug 13, 2008)

I agree with Kgmz I own concrete saws and blades for flatwork and have been in my field for 25 years now and I wouldn't do this. Hire the guy with the right tool for the job. Those guys usually have a track saw that attaches right to the wall and can be plumbed to maintain a clean straight cut. Plus cutting an 8 to 12 inch wall dry will destroy a diamond blade in a matter of minutes thats why they usually cut wet to lubricate and keep the blade from overheating not to mention dry cutting will kill you. Do yourself a favor hire someone, by the time you rent and pay for blade use and all the running around you will probably be 1/2 into his bill. Hire him and make a few bucks on him and go paint something while he is cutting.


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