What to do with exposed block cavities in garage?

[kmcdonou]

I bought a house built in 1950. Not sure when the garage was built, but it has 2x4 walls directly block. No sill seal nor pressure treated bottom plate. Since part of the block is exposed, critters can get in. Also, in the process of ripping out the 1/4" OSB on the walls, I noticed there is only one threaded anchor bolt so far on the exposed 17' section of wall on the left (painted white in the pict), and the back wall, (white and brown) has one anchor point in its 6.5' width. At the anchor points the cavities are filled with mortar.



The open block is contains dirt and stuff:



I am wondering if I should try to fill the cavities with quickrete or some other quick setting mortar and add some additional anchors every 6 feet. I haven't dealt with quickrete or mortar before and am wondering how difficult it will be to fill the cavities and get the right consistency of the mortar.

One thing I worry about with this approach is that there is no sill seal, and filling the cavities adds water that will be wicked into the untreated bottom plate.

Another option is ignoring the unfilled cavities and lack of anchors, and covering the exposed openings with a treated 2x4. The exposed block is 4", and I thought a 2x4 will work close enough.

I am also open to other thoughts. Not looking for perfection, just a good enough solution that at the the minimum keeps critters out of the cavities, but I am willing to address any significant shortcomings short of ripping the garage down.

I appreciate any thoughts you may have.

 

[rsanter]

Get a mirror and see if the bottom has been coated on that base plate.
if it is uncoated, they make a brush on coating/treatment for wood that will be in contact with concrete.
then I would fill those with concrete

 

[kmcdonou]

I'll check tomorrow, but highly doubt it is coated with anything. Nothing was done well in the house, and the garage isn't any different.

For the coating/treatment you are rereferring to, is it able to be applied just to the top of the 2x4 bottom plate and edge on the inside of the garage? Getting under the sill plate, even with open cavities in the block will be tedious and incomplete.

 

[The Cobbler]

filling the cavities adds water that will be wicked into the untreated bottom plate.

fill with spray foam , then fasten a ledger board to cover the block, or forget the spray foam & just install a ledger

 

[dandan111]

If it were mine I’d just fill with stone. Looks like a nice old building.

 

[NUTTSGT]

I wonder if anything was used at all or maybe some tar paper was used between the block and bottom plate.

 

[JohnC1957]

I would use the red duct tape
HD sells for stucco installation and tape 4' plastic roll material to both the wall and the floor. Mix up some concrete and fill the cavities after vacuuming them out. The added water won't cause issues. You could drill holes in the plate and add j hook holddowns before you fill the cavities. Strike the concrete off and you're done.

 

[Bert_]

This is one and done, moisture is not an issue. It will get wet and then it will dry out. No damage.

 

[BillK]

Its been like that for how long ??? It looks like osb which I dont think has been used for that long so its probably newer than the house. Probably 70's or 80's or newer ? There must be some clues or records as to when the garage was built. Look on Historic Aerials and see how far back you can find Aerial views.

Either way I would not worry about the sill seal or lack of PT wood. Its up off the ground level so it will be fine. Fill the block with Sakrete. After a couple of bags you will get the mix figured out.

What does it look like on the outside ??

 

[mm08822]

Get some ready mix mortar and fill the cores. You could add a little bit of gravel to minimize the amount of mortar, but it's about the same effort. Really not that much cost or effort.

As a preventative, before filling the cores, add some termite treatment in each.

If you want, add wedge anchors w/thick fender washers through the sill plate after a 30 day cure.

If the sill plates are still in good condition today, they will probably continue to be going forward.

 

[mm08822]

Maybe pressure wash the floor before any wall covering.....it all depends on your end use how far you want to take it....a tractor shed, work shop or finished garage. It's easier now then when loaded up with stuff.

 

[rsanter]

I'll check tomorrow, but highly doubt it is coated with anything. Nothing was done well in the house, and the garage isn't any different.

For the coating/treatment you are rereferring to, is it able to be applied just to the top of the 2x4 bottom plate and edge on the inside of the garage? Getting under the sill plate, even with open cavities in the block will be tedious and incomplete.

It’s liquid
use a sprayer with a bent tip

 

[johnre]

If there is enough siding coverage at the bottom on the outside to do this:

1. Cut off foundation anchors.
2. Jack up garage a couple of inches with a bottle jack at each corner.
3. Slip in PT 2 x 8 (or 2 x 10?) sill plates to fully cover the tops of the blocks.
4. Put in new foundation anchors that are set in mortar.
5. Set garage back down.

This sort of thing happens all the time when buildings are moved.

 

[Stuart in MN]

The garage has obviously been in place for some time, and based on the one picture the sill plates are in good condition. While pressure treated would be used if you were to start over, I don't think it's worth trying to jack the place up and retrofitting. Same thing with the anchor bolts - while more of them would be preferable, the garage hasn't blown away yet. Seal any gaps with spray foam. You could fill the empty cavities with concrete or even just crushed stone, or leave them alone. For cosmetic reasons you could add another piece of 2x wood, ripped down to the proper width to cover up the blocks.

 

[jkuro]

Let's see, it has lasted 75 years with no problems, let's fix something that isn't broken.
Do some cosmetics to make it look better, but leave it alone. The original builder did a great job.

 

[NUTTSGT]

If the sill is still clear, then I would probably fill the cores with concrete, add anchors after cured properly.

I'm not really sure how far you're taking this remodel or what your goal is in the end. Me, for a nice shop, after core filling, I would add a sill seal, and cover that section of block with a ripped to size 2x4/2x6. I'd also spend an hour or two caulking the joint between the sections of sill plate and at the gap where the block meets sill. Yes, redundant but if anything shrinks and moves, the caulk will help to seal the gap

Then before doing the walls, consider adding an another ripped 2x4/2x6 to the studs already there to gain wall cavity to allow for an extra R value, like R19 or R21.

 

[Bad Habit]

Why go back and add anchors after the concrete? Why not just drill holes now, drop some galv bolts, washers, etc into the void before you pour the concrete?

 

[kmcdonou]

Why go back and add anchors after the concrete? Why not just drill holes now, drop some galv bolts, washers, etc into the void before you pour the concrete?

Yes, that makes much more sense. Wasn't fully thinking through this part enough before responding.

I appreciate all the responses. Very helpful. Now I just need to decide what is "good enough" at the moment.

 

[Leon bee]

Spray foam gun. Done.

 

[ATC]

I'd set another 2x4 on top of the openings. Or, take some flashing and tuck it under the existing baseplate and fold it over the edge of the block with some adhesive on the lip.

 

[Blue Chips]

The way I look at it, even if your garage isn't as old as the house, it's probably been there for many years, and if the sill plates haven't developed any rot yet, they're probably not going to rot unless something has changed that is now causing them to get wet.

If the tops of the blocks are well above grade outside, that helps keep the sill plates dry. However, over the years, debris can build up outside that can transmit moisture into the structure. If that's the case, clear away the debris before it causes damage.

Also, clogged (or non-existent) rain gutters can cause splashing onto the garage. Check to see if the bottom of the siding is getting wet when it rains, and if the siding is getting wet when it rains, that isn't necessarily bad. Just make sure that there is a proper drip edge at the bottom of the siding. If properly installed, the siding should overlap the top of the blocks and should have a gap between the bottom edge of the siding and the blocks to form a drip edge. Keeping that gap clear helps the drip edge function as it should.

As others have mentioned, if you want to secure the garage to the foundation, drill some holes in the sill plates, insert some J-bolts, and pour concrete into the cavities. A short-term exposure to the moisture from the wet cement won't hurt the sill plates at all.

IF you are still concerned about moisture resistance in the sill plates, after the concrete has completely dried/cured (and the sill plates are nice and dry) you can apply a generous amount of thin, penetrating wood preservative to the plates, which is thin enough that it will probably seep most of the way (or possibly all the way) under the sill plates by capillary action. However, as long as the sill plates aren't getting wet, this might be overkill.

 

[Rst277]

Why go back and add anchors after the concrete? Why not just drill holes now, drop some galv bolts, washers, etc into the void before you pour the concrete?

Best option for more anchors if desired.

 

[OccupantRJ]

A run of concrete block with cores filled and anchors imbedded will work, but on my shop I drilled through the sole plate and top plate, then drilled into the concrete for a wedge anchor that runs from the concrete all the way up through the double top plate with large washers on top by using a coupling nut. These are every 4 feet, as I found a load of new threaded rod at a salvage yard. I live in the general NC hurricane path. A similar anchoring only through the sole plate would also work for you.

 

[BombShelter]

No spray foam please! I hate that stuff, it just falls apart and screams cheap fix, maybe in a hard to reach area with critters running around or between walls. I'm a little biased, I see it all the time and have to clean up the mess when it fails a few weeks after installation.

I'd go to Menards and get a black plastic square mixing tub and a hoe. Ask what a good concrete would be for the project, I prefer non-shrink grout for blocks but that's much more expensive. It's great for blocks with water moving through, otherwise regular concrete will shrink a tiny bit allowing water to pass through (with enough pressure) but in your case it should work fine. Just follow the directions on the bag, mix with water, super easy.

Quick drying concrete is not neccessary, mix it up and use a scoop to pour it into the blocks, finish with a trowel. You could probably drill a hole through the bottom plate and attach a bolt with nut and just pour concrete in the hole, sealing the bolt in. Each block can hold roughly 1.5 gallons of space, these can take many bags if the wall is more than one course high.

 

[KenC]

I vote for filled cores, but with concrete mix, not mortar. Just buy sand mix, gravel and a bag of Portland. mix up the sand mix, add gravel until it 'looks' right. Then add a shovel of Portland to makes it stronger and flow better. The gravel is just to reduce the amount of more expensive ingredients. With the added portland you can add a little more water than normal and make the actual filling part go easier.

Wet set a few extra tiedowns. Costs little, helps some if a catastrophe ever strikes and it'll make you feel better about it. That's the most important part.

Then you can add a 2x to make it look better if you want but the filled cores will stop bugs from entering.

Oh, and pre-treating the cores and existing bottom plate to kill whatever insects might try to breach the wall wouldn't be the worst idea.