What is '6-mil poly film'?

olbas_oil

I'm considering LVT planks from Costco on a concrete floor. The installation guide says: 
Concrete subfloors must have a minimum of 6-mil poly film between the concrete and the flooring
What does 6-mil mean in metric terms?  6 mil polyfilm in Google brings up US based suppliers, with what looks like a thin vapour barrier. Screwfix and Tootlstation sell vapour barriers with thickness listed as mu or ga ( I understand that gauge/4 = mu).
I'm not absolutely convinced that I need this at all- the concrete has no damp whatsoever, but I think there would be some advantage in ensuring a dust free environment when laying the planks. 

[Deleted User]

Hi,

this is what I get from google, polyfilm.

neilmcl

olbas_oil said:

I'm considering LVT planks from Costco on a concrete floor. The installation guide says: 
Concrete subfloors must have a minimum of 6-mil poly film between the concrete and the flooring
What does 6-mil mean in metric terms?  6 mil polyfilm in Google brings up US based suppliers, with what looks like a thin vapour barrier. Screwfix and Tootlstation sell vapour barriers with thickness listed as mu or ga ( I understand that gauge/4 = mu).
I'm not absolutely convinced that I need this at all- the concrete has no damp whatsoever, but I think there would be some advantage in ensuring a dust free environment when laying the planks. 

It refers to 6mm of polythene film, which is used as a DPM/moisture barrier when laying flooring onto a concrete base. Have you actually tested your concrete floor for damp?

olbas_oil

[Deleted User] said:

Hi,

this is what I get from google, polyfilm.

I had already done lots of googling before asking my question. Your link tells me that there is a product called '6 mil polyfilm' which is currently unavailable. Is that thicker or thinner than the 125mu or the 300ga polyfilm that is currently available at Screwfix & Toolstation?

olbas_oil

neilmcl said:

It refers to 6mm of polythene film, which is used as a DPM/moisture barrier when laying flooring onto a concrete base. Have you actually tested your concrete floor for damp?

I find it difficult to believe that the film can be 6mm thick. That sounds more like a thin board rather than a film. I'm not sure that '6 mil' = '6mm thick'. Is there a different system in the US for describing thickness?

TadleyBaggie

6 mil is roughly 150µm.

neilmcl

olbas_oil said:

neilmcl said:

It refers to 6mm of polythene film, which is used as a DPM/moisture barrier when laying flooring onto a concrete base. Have you actually tested your concrete floor for damp?

I find it difficult to believe that the film can be 6mm thick. That sounds more like a thin board rather than a film. I'm not sure that '6 mil' = '6mm thick'. Is there a different system in the US for describing thickness?

You're correct, my fault I was looking at something advertised at 6Mil then going on state it was 6mm.

I think Mil is the unit for "thousands of an inch", therefore 6Mil is indeed 0.15mm.