Hard board in mod-50's garage

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bjp_ne_elec

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Meant to say mid-50's - but I can't edit the title.


I have a house I just looked at to estimate a job, and at first I thought the owner had painted the sheet rock black - but on closer inspection, it's some really hard material - almost like concrete. Has anyone ran in to this before, and how did you get around it. It must be the way they used to create a firewall - but what's really weird is they not only have it on the wall between the garage and the house - but it's also on the wall of the back of the garage.

Hoping I don't have to cut any switch boxes in to it, but I do have to run a homerun across it vertically.

Thanks,

Brett
 
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bjp_ne_elec said:
I thought the owner had painted the sheet rock black - but on closer inspection, it's some really hard material - almost like concrete.
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A hard cement like material in a 50s home?

My first thought is asbestos, I would hesitate to mess with it.

Not for my own health as much as liability issues if it gets around the home.
 
Iwire - that was one of my thoughts. I've seen that asbestos insulation on steam pipes and it's rather obvious as it's fibrous and fluffy - but the only way to be sure is to have it analyzed. It's all painted black - so any markings that it may have had - and maybe help identify it - are covered up at this time.

Thanks,

Brett
 
The house I grew up in had Asbestos shingles, if you did not know better they appear to be 1/4" thick cement.

They are not fibrous until you mess with them.
 
77410 - what's "hardy board", and would it have been used between a residential garage and the rest of the house?

How would "hardy board" differ from asbestos board?

Thanks,

Brett
 
Could It be plaster board ,skim coated.There is a lot of it up here used for fire wall,with the rest of the house fiber board,painted
 
The old 3 step plaster system with 3/8 rock lathe, 1/4" plaster base coat and 1/8" plaster finish coat is just about as hard as concrete. It was used for at least 20 years in this area from the late 40's - late 60's.

In any event, I don't know how you'd know what it was until you cut into it. Maybe remove a door or window casing to find an edge?
 
sounds like cement plaster- sort of like stucco, but generally floated smooth.
Great stuff- tough, rot and vermin proof.. May be installed on wire lath.

If it is:
treat it like concrete for anchorages, etc. You should be able to knock holes in it if there are hollows behind it- use a cold chisel. Or cut like concrete with a mini-grinder.

Use appropriate dust control- silica and fiber exposures.
 
j_erickson said:
The old 3 step plaster system with 3/8 rock lathe, 1/4" plaster base coat and 1/8" plaster finish coat is just about as hard as concrete. It was used for at least 20 years in this area from the late 40's - late 60's.

In any event, I don't know how you'd know what it was until you cut into it. Maybe remove a door or window casing to find an edge?
Click to expand...

I have walls as described above in my house. I use a rotozip with a 1/4 inch tile bit and make two passes. One shallow and one deep. It is easier ion the bit. The tool will just bog down if you try and cut full depth and the bit wears out fast.
I put the vacum attachment on the rotozip and connect to the shop vac and the mess is minimal.
 
I have encountered a black type fiber board that is hard like concrete. it was explained to me that it was a type of insulation board. Not sure if this is what you have run across or not. Also could it be a wire mesh covered concrete? the fibre board I spoke of was also in a commercial/industrial install. never seen it in a home before. Hard stuff. tears up a sawzall blade quick.
 
Thanks for all the replies. This board, which appears to come in 4' x 8' sheets is nailed directly to the studs, and I did find an edge and it's gray in color.

I'm going to go with the assumption that this stuff probably is asbestos, and steer clear of even touching it - and I have told the homeowner that already. I have to be real creative how I get around now - but hey, if this job wasn't challenging, I'd probably be doing something else.

THanks

Brett
 
Has anyone mentioned that what you have could be "homosote". Unsure of the spelling. There are 2 types of products made which I've heard referred to as homosote. It is basically an insulating board, as dingokangaroo mentioned, but was used in residential applications. The board was meant to be a finished product. Of the 2 types, one had a "hard" finish, and one had a "soft" finish. I'm not sure if it contained asbestos.
 
Could it be homasote? This product years ago came with basically 2 finishes. A soft finish when it would be an interior finish, and a hard finish if it were exposed to the weather. It may be harmless. Might warrant a little further investigation.
 
Oops, posted about homasote, then did a quick google search. When I came back, my post wasn't there, so I thought I forgot to submit it. Instead, I didn't refresh after hitting all the "back" buttons.
 
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