1924 Drawings - Mastic Floor Finish

[archeng59]

I am working on renovations to a building constructed in two phases. The building was constructed as an automobile manufacturing facility. Phase 1 was a four story building constructed in about 1916. Phase 2 was a 2 story addition constructed in about 1925. We were fortunate that the owner had copies of the original construction documents for both phases and some construction photos for phase 1. The building is being renovated into a hotel. The drawings for the 2 story addition specifies a 1 1/2" thick mastic floor finish in an area where a penthouse is being renovated into a guest suite. Does anyone know what a mastic floor finish is? I know that mastic is an adhesive but what did that mean in the mid-1920s? Likely the same type of thing but at 1 1/2" thickness, I am wondering if it might be a gypcrete or regular concrete topping with a mastic sealer. Looking through some old texts and a

http://www search

has resulted no additional useful information. Curious if anyone on here has encountered this material previously.

 

[IRstuff]

https://law.resource.org/pub/in/bis/S03/is.1196.1978.pdf

and

http://tenders.hpcl.co.in/tenders/t...l/Appendix G - Specification for Flooring.pdf

seem to suggest that it may be a bitumen-based material

TTFN
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[archeng59]

Interesting. Thanks.

 

[paddingtongreen]

They used "mastic" for some factory floors in the UK when I started work. That was was a kind of blacktop, the mastic being the binder.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[dhengr]

Archeng59:
I second Paddington’s thoughts on “mastic floor finish,” also called ‘mastic asphalt.’ 1 or 1.5" thicknesses were common. It was an asphalt type floor topping, not really a structural component; smooth, hard, no seams, water tight, good wearing surface.

 

[archeng59]

Thanks, everyone. That's more than I knew about it a few hours ago!

 

[charliealphabravo]

It might be a good idea to have it tested for asbestos.

 

[archeng59]

Asbestos testing is being done on surfaces that will be removed or modified. In the case of the mastic topping, it will not be removed or modified. I am reviewing the existing framing for load capacity and did not know what to allocate for the weight of the mastic floor finish.

 

[racookpe1978]

I agree. Possible asbestos locked into the mastic. It's NOT friable nor air-borne, and will be UNDER the next floor covering, and is NOT exposed to the public nor the workers, but some people get hyper nowadays. Use a "historical" exception so you don't have to remove it?

 

[charliealphabravo]

In industrial settings where asbestos is identified and there is no immediate need to remove it I have seen labels posted to identify the asbestos and provide notice for any future work. I thought that was a pretty fair solution.