Cutting access hole through foundation wall into crawl space

[spitfire557]

Hello all. My house has an addition built onto it which is above a crawl space. The original portion of the house has a full basement. For whatever reason, they never made an access point into this crawl space. We are currently renovating this addition (master bedroom/bathroom) and I need access into the crawl space for plumbing relocation, not to mention it's just a good idea to have access available.

My question is this, I was originally going to cut a 2'x3' hole through the cinder block foundation, and remove the top course of block about 12" past each side of the access hole, and install a header in place of this top course. The joists here run parallel with the foundation wall so I'm not even sure a header would be necessary, but good peace of mind. Before I started cutting, I went through the subfloor from the addition side and got a sneak peek into the crawl space. What I found was that the joists for the addition run perpendicular to the foundation wall, and are hung on a ledger board which is concrete bolted into the top course of block.

I'm now very hesitant to cut through the foundation wall as it's obviously load bearing. Any ideas on how I should proceed here? One idea is to temporarily support the joists near the future access hole, and then eventually bolt the existing ledger board to the newly installed header. I'm still hesitant to do this though, as I don't have a ton of experience with this type of situation. I've included some photos of the wall from both the basement side and the crawl space side.

Thanks in advance!

 

[duneslider]

If this were a bit lower in the block I would say just cut it out and put a steel lintel in. Being this close to the top that still might work fine. I have gotten to the point that I would hit up an engineer to give me a solid spec to follow. The engineer in my area that I use would probably only charge 3-500 for it.

I am also concerned about all your joist hangers and the fact that they don't have many nails. Every hole should be filled, looks like they saved a few bucks by not putting all the nails in.

 

[Jackfre]

Whichever way you go n the cut-out, it looks like you are in for the purchase or rental of a Simpson hanger nail gun. Maybe you can rent one. Duneslider‘s was a good pick-up on the paucity of nails and it would be a nightmare trying to do those in place. The nail gun will let you roll through it. If everything is hanging all right as the floor currently sits, I would build a temp support inside, and make it at least double the width of the cut-out. Add your header and re-attach the ledger. Now, the question is, Is everything in line in that floor now?

 

[tominboise]

I have seen where the access to a crawl space like this is a hatch cut and framed into the floor of the closet or utility room. Would something like that work in your case?

 

[larry_g]

Have you done a good search for a trap door in the floor?

lg
no neat sig line

 

[nmk_61802]

Hello all. My house has an addition built onto it which is above a crawl space. The original portion of the house has a full basement. For whatever reason, they never made an access point into this crawl space. We are currently renovating this addition (master bedroom/bathroom) and I need access into the crawl space for plumbing relocation, not to mention it's just a good idea to have access available.

My question is this, I was originally going to cut a 2'x3' hole through the cinder block foundation, and remove the top course of block about 12" past each side of the access hole, and install a header in place of this top course. The joists here run parallel with the foundation wall so I'm not even sure a header would be necessary, but good peace of mind. Before I started cutting, I went through the subfloor from the addition side and got a sneak peek into the crawl space. What I found was that the joists for the addition run perpendicular to the foundation wall, and are hung on a ledger board which is concrete bolted into the top course of block.

I'm now very hesitant to cut through the foundation wall as it's obviously load bearing. Any ideas on how I should proceed here? One idea is to temporarily support the joists near the future access hole, and then eventually bolt the existing ledger board to the newly installed header. I'm still hesitant to do this though, as I don't have a ton of experience with this type of situation. I've included some photos of the wall from both the basement side and the crawl space side.

Thanks in advance!

Are you sure those are bolted into the concrete block? If so the MBR floor should be lower than the rest of your house. To me that looks like lag bolts into the original exterior rim joist. It also looks like the rim joist is 2x10 or 2x8 which should span a single joist across an 36" opening.

Those joist hangers need a lot more nails/ screws too

 

[hefnerconstructionlc]

I would just knock two blocks out per row. To gain access to the other side. Whatever falls falls. I mean that's really only one joist span to sag temporarily. The band and other joist will also pick up a good bit of the load. Then when you're on the other side put a jack underneath to straighten everything up. Then reattach and make the support the way you want. Place your nnice steel lentil you should be good to go.

 

[spitfire557]

Are you sure those are bolted into the concrete block? If so the MBR floor should be lower than the rest of your house. To me that looks like lag bolts into the original exterior rim joist. It also looks like the rim joist is 2x10 or 2x8 which should span a single joist across an 36" opening.

Those joist hangers need a lot more nails/ screws too

Appreciate everyone's responses. I will definitely be nailing the rest of those hangers, hadn't considered that until now.

And yes - the master bedroom is lower than the rest of the house. I have no clue why they did it like that and it makes just about everything more difficult (I posted another thread about drainage/grading issues created by this "sunken" bedroom).

As for the trapped door idea, I've been considering that heavily as it would eliminate screwing with the foundation wall altogether. We have a decent sized closet in the master bathroom that I could put the trapped door in. Only issue there is that I planned on tiling the floor in the bathroom/closet, so I'm not sure what to do with the trapped door finish wise.

 

[HoosierBuddy]

so I'm not sure what to do with the trapped door finish wise.

You certainly wouldn't be able to use tile. My mom has one in a half-bath and they just didn't fasten the carpet down. Not the greatest solution, but for hers you roll the carpet back and then remove a section of the floor.

It might be worth it to have a foundation specialist give you a quote on cutting a hole in the foundation and installing required bracing. That's what I'd do unless there was a closet or such where a trap door wouldn't be an issue down the road.

 

[duneslider]

I have put access doors in floors with tile. We matched up the "door" size with the tiles and used some trims around the tiles and didn't grout them. The panel had to be lifted out, it was sort of heavy, had insulation attached to the bottom too. The customer really never went down there and it was just there for those just incase times. I think they ended up having a rug over the whole thing anyway.

We drilled holes in 2 tiles and there were threaded inserts in the framing and they had some bolts with a handle welded on. Just screwed them in and lifted it out. I thought it looked fine and worked fine but the rug made it so you couldn't even tell.

 

[rayra]

there's this hot new invention called the 'arch'. Maybe there's some Romans on the board that can explain its use.

In seriousness, try to cut the block in a way that retains the support of the staggered arrangement of the blocks, stay away from the top course where the ledger is bolted. And the ledger itself becomes almost self-supporting in this regard as you are only undermining a small portion of it and all of the ledger board remains secured along its length. That **** shouldn't be going anywhere.

 

[spitfire557]

there's this hot new invention called the 'arch'. Maybe there's some Romans on the board that can explain its use.

In seriousness, try to cut the block in a way that retains the support of the staggered arrangement of the blocks, stay away from the top course where the ledger is bolted. And the ledger itself becomes almost self-supporting in this regard as you are only undermining a small portion of it and all of the ledger board remains secured along its length. That **** shouldn't be going anywhere.

I feel like that could backfire pretty easily though. Almost like playing a game of Jenga with my foundation. LOL

I'll do some more research on it tonight, but I'm leaning towards the trapped door. Or if not that - I'll probably hire a foundation guy to do the work while I cringe upstairs.

I suppose I could always tile around the door, and just finish the door off with hardwood. It'll look strange but I could position it in the closet where there'll most likely be a rug anyway.

 

[jack stand]

I don't think you need a header getting in your way. You could do several things, one screw, bolt, tapcon a "post", pressure treated vertically on each side of the new access opening. 36" or 48" isn't a great load unless you have a hot tub sitting over it, it's just floor load.
The other is to jamb out your new opening and let the verticals become a "jack" by extending them under the additions band for support.
Think of the load, if I understand this properly it's not very much of one and the floor level difference allows you to take all the block out and double the backside of your now free floating bedroom band and transfer that load via the new 2x jambs down to the (now) threshold of the new opening that happens to sit on the foundation.

 

[PoorUB]

Personally, I don't see and issue just blowing a hole a couple feet wide. On the one side the floor joists run parallel to the foundation to the only load it the wall above. On the other side with the joists running to the wall you could anchor a piece of 4" C channel about six feet long, centered over the opening, butted up to the rim joist that is screwed to the wall. Make you hole a couple feet wide instead of 3 feet. Go taller if you need to.

The mention of a couple 4x4 post is good too, if you can get them down to the footing.

I would blow a hole in the wall before putting in a trap door.

 

[spitfire557]

Actually, just had a brain fart leave my head and realized I could put the trapped door in closet of my daughter's room, which is also built above the crawl space. Her closet has laminate hardwood so it would be much easier than working with/around tile.

 

[spitfire557]

I don't think you need a header getting in your way. You could do several things, one screw, bolt, tapcon a "post", pressure treated vertically on each side of the new access opening. 36" or 48" isn't a great load unless you have a hot tub sitting over it, it's just floor load.
The other is to jamb out your new opening and let the verticals become a "jack" by extending them under the additions band for support.
Think of the load, if I understand this properly it's not very much of one and the floor level difference allows you to take all the block out and double the backside of your now free floating bedroom band and transfer that load via the new 2x jambs down to the (now) threshold of the new opening that happens to sit on the foundation.

Very good point. I suppose I'm just less intimated by cutting a hole through my floor versus cutting a hole through my foundation.

 

[BillK]

One thing to consider with the trap door is the floor joist spacing ? If it is 16" on center you will probably have to cut at least one joist.

 

[spitfire557]

One thing to consider with the trap door is the floor joist spacing ? If it is 16" on center you will probably have to cut at least one joist.

I'm a relatively small framed guy so squeezing through a 16" opening is no issue for me. I did it quite comfortably when it went through the subfloor the other day. I could always box the joists out though, and make it nicer for the next guy though.

 

[Uncle murph]

Hello all. My house has an addition built onto it which is above a crawl space. The original portion of the house has a full basement. For whatever reason, they never made an access point into this crawl space. We are currently renovating this addition (master bedroom/bathroom) and I need access into the crawl space for plumbing relocation, not to mention it's just a good idea to have access available.

My question is this, I was originally going to cut a 2'x3' hole through the cinder block foundation, and remove the top course of block about 12" past each side of the access hole, and install a header in place of this top course. The joists here run parallel with the foundation wall so I'm not even sure a header would be necessary, but good peace of mind. Before I started cutting, I went through the subfloor from the addition side and got a sneak peek into the crawl space. What I found was that the joists for the addition run perpendicular to the foundation wall, and are hung on a ledger board which is concrete bolted into the top course of block.

I'm now very hesitant to cut through the foundation wall as it's obviously load bearing. Any ideas on how I should proceed here? One idea is to temporarily support the joists near the future access hole, and then eventually bolt the existing ledger board to the newly installed header. I'm still hesitant to do this though, as I don't have a ton of experience with this type of situation. I've included some photos of the wall from both the basement side and the crawl space side.

Thanks in advance!

Cut it,but make life easy and make the hole 32” wide,if the ledger is correctly attached you shouldn’t have to add anything,if it’s not,make that your first priority.You should also finish the teco installation that the original contractor neglected.

 

[Uncle murph]

Hello all. My house has an addition built onto it which is above a crawl space. The original portion of the house has a full basement. For whatever reason, they never made an access point into this crawl space. We are currently renovating this addition (master bedroom/bathroom) and I need access into the crawl space for plumbing relocation, not to mention it's just a good idea to have access available.

My question is this, I was originally going to cut a 2'x3' hole through the cinder block foundation, and remove the top course of block about 12" past each side of the access hole, and install a header in place of this top course. The joists here run parallel with the foundation wall so I'm not even sure a header would be necessary, but good peace of mind. Before I started cutting, I went through the subfloor from the addition side and got a sneak peek into the crawl space. What I found was that the joists for the addition run perpendicular to the foundation wall, and are hung on a ledger board which is concrete bolted into the top course of block.

I'm now very hesitant to cut through the foundation wall as it's obviously load bearing. Any ideas on how I should proceed here? One idea is to temporarily support the joists near the future access hole, and then eventually bolt the existing ledger board to the newly installed header. I'm still hesitant to do this though, as I don't have a ton of experience with this type of situation. I've included some photos of the wall from both the basement side and the crawl space side.

Thanks in advance!

Also,trap doors **** for almost everything,duct work,pipe,framing lumber,all but impossible to pass through a trap over a crawl space.

 

[mikedodge]

Make the hole with a lintel. Its no different then a basement window. From those pics it looks like it's pretty straightforward from both sides. If you're worried get a place that does foundation work in to do it.

 

[The Cobbler]

the rim joist in the crawl space will hold a lot more weight than you're giving credit . especially for short term. I would knock out your opening in a heart beat then double the rim joist with and a jack on each side if you think you need to .

 

[PoorUB]

For whatever it us worth. I have several 32 inch gaps in the foundation walls of my house. Each basement window has a single 2x8 on edge spanning the openings that support the floor and walls above.

 

[CJM8515]

my house has a similar idea. they made a full foundation and added onto it. they just cut a large hole in the original foundation. im not sure how many years its been like this-but the cinderblock sides havent caved in and the large header they put there doesnt seem like it moved. reality is i think your overthinking it.

 

[CraigStu]

We don't know the locations (as in floor plan) of your bath upgrade or daughter's closet but I'd do the door in the floor in a heartbeat. If worse comes to worse like uncle murph's thought about getting materials down there, cut a half block square hole in that foundation, and pass material through there. Cut half of one of the lowest blocks in your taped area and you don't even need to think about losing foundation support. BTW if you don't have one, buy a plastic snow sled and tie a 4 ft piece of rope to the front. That is so nice for pulling behind you w/ your tools/supplies on it while you crawl across the dirt. BTW2, after you are completely done, go back down there and be sure that all the plastic laying on the dirt is perfectly sealed w/ good tape. I didn't do that in one house and 15 years later found black mold when we went to sell. The mold was over spots where I had messed up the plastic crawling around under there running wires etc. $4k was the bill for the fix (buyers insisted on a certified company doing the fix and giving them a certificate) for my stupidity.

 

[spitfire557]

I definitely agree that I'm most likely overthinking it. There's been a ton of good ideas in this thread and I appreciate the responses. Still torn as to the route I'm going to take, will try to get back into the crawl space this weekend to finish up nailing the hangers and ponder some more.

 

[firebirdparts]

The ledger will be strong enough if you create a 3 foot or 4 foot gap in its support. That's a short gap in its support relative to its strength. preferable if you don't make that gap under a perpendicular wall. Make it under an open part of the room. I would think the larger problem is being able to make your crawl hole below it in elevation. I would not cut it and that means your self will have to go under it.

 

[Pen & Wrench]

We had to make an access to a crawl space in a rental house we sold this year. We knew there were issues with the floor joists but we figured it was braced and more than sturdy enough for our purposes, but technically it wasn't actually done correctly. When we sold it, we had to put in a support beam to pass inspection. It was a block basement and I enlarged one of the basement windows. I used a diamond wheel on an angle grinder and carefully used an air chisel, and enlarged the basement window opening and built a cover that had a window to open or close for ventilation. It could have been done more attractive, but it did the job for us and it passed inspection. The opening didn't match any stock window I could buy, so I made it fit within the access cover frame I built. There was a curtain covering the original window and we figured the curtain could go back and it would look pretty much like it did before, except that now you could actually get inside the crawl space.

 

[Pen & Wrench]

I may not have been clear, in my previous post, I deepened an existing basement window, did not make it any wider, and the support stayed the same as it was with the original window, not sure if I would do it exactly that way in a new construction but it seemed to work in the existing home and the home inspector and city building inspector was okay with the way it was done.

 

[joes169]

the rim joist in the crawl space will hold a lot more weight than you're giving credit . especially for short term. I would knock out your opening in a heart beat then double the rim joist with and a jack on each side if you think you need to .

Yup, this is exactly what we do on a regular basis. Unless there's a grand piano parked on top of those 1 or 2 floor joists, it's not going anywhere. As other's suggested, the lack of nails in the joist hangers is actually far more concerning...........

 

[spitfire557]

the rim joist in the crawl space will hold a lot more weight than you're giving credit . especially for short term. I would knock out your opening in a heart beat then double the rim joist with and a jack on each side if you think you need to .

Appreciate the response. Did you mean double the rim joist width across the crawl space opening?

 

[The Cobbler]

I think if you get the concrete block out you could slide a pc of 2x up inside to beef up the rim joist . but, I don;t know if you need to really for such a short span

 

[spitfire557]

Finally had time to get back down there and secure the joist hangers. Not only did they only use one or two nails per hanger, but they used roofing nails. Needless to say, I finished off the rest of the hangers with appropriate hanger nails and removed/replaced what roofing nails I could.

The hole will be punched through the foundation tomorrow. I have faith that the span is short enough that temporary bracing is not required, and I'll add a header just to be safe. I was looking at it a bit more closely today, and the last 8' or so of the rim joist is actually resting on top of a cinder block wall that runs perpendicular to the foundation. So I think they lag bolted the middle portion of the rim joist to the exisiting foundation as added insurance.

 

[The Cobbler]

 

[spitfire557]

Mission accomplished. Was much easier than I had envisioned. You can see in the one photo was I was saying about the original rim joist resting on top of the top block, and the addition's rim joist being bolted to foundation wall.

Ended up sistering 5' of the original rim joist and put a 4x6 header in, and lag bolted the addition's rim joist to the header. If anything, it's stronger now than it was before. I even got fancy and mixed up some quick setting concrete and smoothed out the sides of the opening. I'll frame it out with some 2x8 tomorrow to give it a more finished look.

 

[The Cobbler]

well done!

 

[rburke65]

I have a similar hole cut into the crawl space in my home. It’s 2’x3” and They just made a frame using 2”x 12”s On all 4 sides

 

[Joemctag]

I have seen where the access to a crawl space like this is a hatch cut and framed into the floor of the closet or utility room. Would something like that work in your case?

Done that several times. A 14-1/2” wide by, say, 24” long opening between floor joists worked for me. No need for headers. Might have to re-route a romex cable or something.

 

[jrsavoie]

Whichever way you go n the cut-out, it looks like you are in for the purchase or rental of a Simpson hanger nail gun. Maybe you can rent one. Duneslider‘s was a good pick-up on the paucity of nails and it would be a nightmare trying to do those in place. The nail gun will let you roll through it. If everything is hanging all right as the floor currently sits, I would build a temp support inside, and make it at least double the width of the cut-out. Add your header and re-attach the ledger. Now, the question is, Is everything in line in that floor now?

I might consider making the temp support, a permanent support since it's in the crawl space and won't be seen or in the way.

I might consider using screws for the hangers. Short fat stainless. Or longer tapcons/consert screws into the block behind. I have always Preferred Hilti brand for concrete screws.

Maybe advertise for a nail gun.
Check the for sale sections, Marketplace, Craigslist.

 

[ohmavrk]

Mission accomplished. Was much easier than I had envisioned. You can see in the one photo was I was saying about the original rim joist resting on top of the top block, and the addition's rim joist being bolted to foundation wall.

Ended up sistering 5' of the original rim joist and put a 4x6 header in, and lag bolted the addition's rim joist to the header. If anything, it's stronger now than it was before. I even got fancy and mixed up some quick setting concrete and smoothed out the sides of the opening. I'll frame it out with some 2x8 tomorrow to give it a more finished look.

just curious what did you use to cut your hole?