Attaching 2x4 to cinder block wall

I am looking for suggestions on how to attach a 2x4 to a cinder block wall.

Here is the scenario. The 2x4 will be running horizontally on the interior of a basement wall below the ground level. It will be attached flat to the wall similar to a ledger board. The wall is made of cinder block (not cement block I assume because the property was built in 1948). The basement was completely gutted down to the exterior walls and all new walls were framed out with 2x4's for a complete remodel of a basement level apartment. All of the exterior walls were framed out with 2x4's with the studs about

1/4-inch away from the wall and secured at the top and bottom with top plates and bottom plates.

However, about 15 feet of one exterior wall has a 4-inch PVC sewer line running along the bottom of the wall about 6 inches above the floor level. So, the wall above that sewer line cannot be attached to a bottom plate along the floor because the sewer line is in the way.

What I want to do is run that wall down to a wood "bottom plate" that is actually attached to the wall instead of to the floor. To do that, I want to attach a horizontal 2x4 flat to the cinder block wall with anchor bolts of some sort. Then nail a second 2x4 on top of that to create the new "bottom plate" for the wall above the sewer line.

Since the 2x4 will be attached to the wall below the outside ground level, I was thinking of using some type of rubber or similar strip to try to isolate the wood from making direct contact with the cinder block to avoid moisture and termite problems. And, maybe I would use pressure treated wood for that one 2x4 -- but I'm not sure about that idea.

So, one question I have is what to use between the wood and the wall -- rubber, tar paper, or what?

And, the second question is how to attach the first horizontal 2x4 to the wall. I know there are different types of anchors that could be used. One possibility would be anchors that go through the cinder block where the hollow part is and anchor from the back. Another possibility would be anchors that just get drilled into the cinder block but make sure that they go in where the block is solid all the way through.

Any suggestions or ideas would be appreciated -- especially regarding what type of anchors to buy and use to secure the 2x4 to the wall.

Thanks.

Reply to
RogerT
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I'd use pressure treated and tar paper. _______________________

Tapcon screws Any of the various proprietary ,expanding types; eg, Hilti Lead anchors Toggle bolts (in core area, not web)

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Reply to
dadiOH

Use Tapcons.

[...]

Why not? This seems like an ideal application for treated wood.

Nothing. If the basement is dry, you don't need anything like that. If it's not dry, then you should fix your moisture problems first.

Tapcons, as noted above.

Reply to
Doug Miller

Why are you needlessly making building this wall more complicated than it needs to be ?

Box in the sewer pipe by constructing the wall where it can run from floor to ceiling unobstructed... The tenants in this basement unit are not going to like having an exposed pipe with a wall built cantilevered out above it...

All sorts of lovely stuff will accumulate behind such a pipe, spiderwebs, dust bunnies, clumps of hair that build up, the errant sock that gets lost, etc... Not to mention that the sound of water isn't so relaxing when you know it is sewage in the pipe...

Just build an unbroken wall that has access panels located wherever there are clean outs in the sewer line or a fitting that turns a corner where the pipe changes directions... You don't need access to the entire pipe all of the time, if you have a repair that needs to happen in the future then you would cut the sheet rock away to access the pipe... By building a proper unbroken wall, you will be able to properly insulate the entire wall both against the chill of the outside wall as well as the sound of the water flowing in the sewage pipe...

Any other solution is just a folly...

~~ Evan

Reply to
Evan

That seems to be a recurring theme on this usenet group... I understand that not everyone knows how to do everything, but when someone doesn't know how to approach a project, why do they always devise the most cockamaime plans?

If you don't know how to do something ASK HOW TO DO IT. Don't present your 50-step plan that involves hanging a wall from another wall by cantilevering it off the edge of a 2x4. You're fixing a house, not building a replacement for the space shuttle.

When things get that complicated, that's a HUGE RED FLAG telling you to STOP, and seek professional help. Home improvements are NEVER that complicated.

Cantilevering the wall just isn't going to work. It's going to sag over time as the nails pull out. Plus as you said, the sewer pipe is left exposed.

The bottom plate needs to be fully supported, and the sewer pipe needs to be covered.

Simple solutions are best: As you said, bring the wall 6" into the room and build it properly, floor-to-ceiling. You lose 6" of room, but the job is done properly, and it will last. Get creative and build alcoves into the wall to make use of the "wasted" space... Book shelves, or an entertainment center.

The next-best solution is to build a platform around the sewer pipe, then build your wall in the original location off that platform. Still a lot simpler than trying to engineer a cantilevered wall that nobody has ever done before.

Reply to
mkirsch1

Exactly. I think it was Ronald Reagan who said: "Those who think there are not simple solutions to complex problems just haven't tried hard enough."

Or maybe it was Dom Deluise. I forget.

Reply to
HeyBub

The same foam they use on top of the cement or cinder block. It's usually pink. It's also good to put it under the wood attached to floor. It's code here to use pressure treated, but only on Holmes on homes, do they always use a polyethylene foam moisture break.

That's prevents using polyurethane glue as extra strength against the wall, but unless the wood is thoroughly dried, it's not going to stick anyway. I thick your stuck with either toggle bolts, which can rust, or some epoxy based holding devices.

Greg

Reply to
gregz

I'd give up the 6-8 inches of room space, and move the wall in. You can always do flush bookcases into the dead space if you want to jazz up the apartment. I'd also band the bottom of the wall with a wide trim plate that can be removed to get to the pipe when needed, without major demo work. Old cinderblock or concrete block walls are risky to mess with- the mortar between them loves to let go without warning, when any strange forces (like a hammer drill) are applied.

Reply to
aemeijers

rote:

Treated wood is not 'rot proof' it _will_ rot, just takes longer. Do something to keep the moistur away from the wood.

Harry K

Reply to
Harry K

Errm...unless the wall was built with 2x4 on the "flat" it will take

8" or more (depends on the actual outsid diameter of the pipe) of room space. Shouldn't be a deal breaker though. It will only be 4" more than what he is planning anyhow.

Harry K

Reply to
Harry K

Unless the OP lived in an area totally devoid of any fire safety codes, using a large piece of wooden trim at the bottom of the wall rather than sheetrocking first would be a violation -- the fire compartment wall would be incomplete...

Usually a minimum fire rating of 90 minutes between the differently occupied units is required of demising walls/ceilings...

~~ Evan

Reply to
Evan

The concrete block wall and all the dirt on the other side don't count? This is a basement apartment. But you do sorta raise a good point- there should be fire stops at the tops of the new walls, to divide the stud bays and dead space behind wall off from the bays between the ceiling joists.

Reply to
aemeijers

Thanks to all for the replies. We ended up going with the suggestion to use Tapcons to secure the pressure treated horizontal 2x4 to the wall, and we used "sill seal" that we had on hand between the 2x4 and the wall. We placed the Tapcons every 16 inches in the vertical mortar joints between the cinder blocks. Then we used a nailing gun to attach the second regular wood

2x4 to the first pressure treated 2x4. It all worked perfectly and that part of the job is done.

Regarding the suggestions about building out the wall using 2x6's etc., it's a little hard to explain here exactly why we didn't do that. But, the brief version is that the sewer pipe will not be part of an exposed wall. Instead, kitchen base cabinets will be in front of the sewer line in a kitchen, and a bathroom tub/shower will be in front of the the sewer line in a bathroom. And, yes, there are fire stops at the top of the walls etc.

Again, thanks for the ideas. The Tapcons worked great.

Reply to
RogerT

Thanks for the update. Too many people ask a question and then we never find out what the final outcome was.

Harry K

Reply to
Harry K

Fire could still enter the bottom of the wall, the goal of creating fire compartments is that all six sides of the compartment are contiguous with as few disruptions as possible...

All holes, no matter how small must be fire-stopped... Every pipe and wire...

Leaving a firewall open at the bottom (i.e. sheetrock incomplete) would be allowing fire to enter that wall cavity even if it is firestopped at the top and is not the best construction technique...

Nor is installing cabinets in a kitchen without sheetrock behind them, that is just asking for pest control problems in the future as well as other issues...

What is the OP's issue with building a wall straight up from the floor ?

Needless complexity where it ISN'T required... I bet this wall doesn't have enough blocking in it to be rigid enough... I wonder how it will hold up given that everything on the wall will essentially be hanging from the top plate...

~~ Evan

Reply to
Evan

Also appreciate the update. But to hang out here and try to be a solution-giver, you gotta start thinking like a teacher or field medic- you do the best you can, and hope you helped, but learn to live with the fact that most of the time, you'll never know how it came out.

Reply to
aemeijers

A 2x4 on the flat at the bottom as he installed _is_ a fire stop. Or do youi think that they bother to put sheetrock on the firestops that inside the walls?

Harry K

Reply to
Harry K

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