Quick-Step vinyl planks - perfectly level floor?

[pulck]

I'm a novice DIYer trying to lay Quick-Step vinyl flex planks (floating) in my recently finished loft conversion. The loft floor is chipboard panels and I've bought Quick-Step comfort underlay.

However, the floor isn't totally level. Some of the chipboard panels are maybe 1-2mm proud of adjacent panels.

Also, when I lay a long flat length of wood on the floor, there appears to be as much as 5mm height difference between one part of the room and another.

These are just localised dips. These are height differences across the room, so I'm guessing levelling using compound would be very tricky, probably beyond my abilities.

If I went ahead and laid the vinyl, will I see problems later on? How would a good fitter go about this?

 

[Koolpc]

You need to get it as level as possible from the get go.

 

[blup]

A decent underlay should deal with that kind of uneveness

Blup

 

[Deleted member 174758]

These are just localised dips. These are height differences across the room, so I'm guessing levelling using compound would be very tricky, probably beyond my abilities.

If I went ahead and laid the vinyl, will I see problems later on? How would a good fitter go about this?

Well, after bitching about a new floor having dips in it (it should be flat), and having steps where the boards meet (it shouldn't have any steps - if the installer had come into the 21st century and used glued and screwed T&G chipboard it wouldn't have), a commercial fitter would lay down some SLC to take out the hollows and steps before fitting the finished flooring. I have seen this done many dozens of times in shop and office fits, but rarely heard of a domestic fitter following suit. A newly fitted chipboard floor should really be like a billiard table. As said, though a decent underlay should cope with it

 

[pulck]

Well, after bitching about a new floor having dips in it (it should be flat), and having steps where the boards meet (it shouldn't have any steps - if the installer had come into the 21st century and used glued and screwed T&G chipboard it wouldn't have), a commercial fitter would lay down some SLC to take out the hollows and steps before fitting the finished flooring. I have seen this done many dozens of times in shop and office fits, but rarely heard of a domestic fitter following suit. A newly fitted chipboard floor should really be like a billiard table. As said, though a devent underlay should cope with it

Thanks. I could moan but, being ignorant about these things, I'm never entirely sure what standard I should expect from builders.

What do you consider a decent underlay? Presumably something more than Quick-Step's own 'comfort' underlay? (it's 1.15mm thick)

 

[blup]

I think something that thickness pre supposes a near perfectly flat sub floor.

Blup

 

[pulck]

I think something that thickness pre supposes a near perfectly flat sub floor.

Blup

Can I put something under the underlay (!) to level it? I think I'm supposed to use the Quick-Step underlay in order to get their warranty.

If not how about something like this (2mm thick) or this (3mm)?

I'm guessing it's a problem if it's too thick/spongy, as you don't want any movement with vinyl planks.

Any recommendations much appreciated.

 

[SpecialK]

Gentle dips dont matter. The joints will though. Can you sand them down?

 

[pulck]

Gentle dips dont matter. The joints will though. Can you sand them down?

Not sure I could sort it out with my toolset/competence. I could probably make the step a little bit smoother, but I doubt I could produce a gradual slope.

Here's the worst step. Wouldn't the 2mm or 3mm underlays equalise this?

 

[SpecialK]

Not sure I could sort it out with my toolset/competence. I could probably make the step a little bit smoother, but I doubt I could produce a gradual slope.

Here's the worst step. Wouldn't the 2mm or 3mm underlays equalise this?

View attachment 294882

You would need a floor sander to take that out! Maybe some flexible screed or something?

 

[Deleted member 174758]

Maybe some flexible screed or something?

Do you ever get that feeling of deja vu?

BTW, it isn't really such a good idea to sand chipboard flooring. The relatively thin outside skins are a lot denser than the core. Heavy sanding can easily result in sanding through the skin which will result in the chipboard being weakened.

 

[cjcoffin]

You say the loft conversion is "recently finished". I would complain to the builders that the floor does not meet a reasonable standard of workmanship (it doesn't) and in particular it does not meet the requirements for laying the Quickstep planks on top of it, their underlay will not be sufficient. Get them back to sand it.

If they will not fix it and it isn't bad in a lot of places then the best way IME to deal with ~1mm steps in floorboards is to get hold of the thck paper underlay used for some kinds of floor covering and build up the level using several layers of increasing width. Start with a 2 ins wide strip at the bottom and increase by 2 ins at a time. Tear the paper rather than cutting as it will give a slightly jagged feathered edge. Secure with glue or staples.

 

[pulck]

Do you ever get that feeling of deja vu?

BTW, it isn't really such a good idea to sand chipboard flooring. The relatively thin outside skins are a lot denser than the core. Heavy sanding can easily result in sanding through the skin which will result in the chipboard being weakened.

I don't think I'm going to try my hand at sanding it! I'd make it worse rather than better.

Can I just confirm if the underlays I suggested are any good or not?

Otherwise I suppose I'm left with the option of getting a professional in, since I'm pretty sure screeding a chipboard floor is beyond my limited ability.

 

[Deleted member 174758]

Sorry to say, but whether or not you like it, the best way to level this now is to use an SLC, and if needs be sand that afterwards. The best way to find an appropriate underlay is always to talk to the manufacturer of your flooring. They will tell you which products are suitable and compatible.

It is always better to do a job right, and put the floor in properly, in the first place, though

 

[pulck]

You say the loft conversion is "recently finished". I would complain to the builders that the floor does not meet a reasonable standard of workmanship (it doesn't) and in particular it does not meet the requirements for laying the Quickstep planks on top of it, their underlay will not be sufficient. Get them back to sand it.

If they will not fix it and it isn't bad in a lot of places then the best way IME to deal with ~1mm steps in floorboards is to get hold of the thck paper underlay used for some kinds of floor covering and build up the level using several layers of increasing width. Start with a 2 ins wide strip at the bottom and increase by 2 ins at a time. Tear the paper rather than cutting as it will give a slightly jagged feathered edge. Secure with glue or staples.

I may speak to them, but I favour sorting it out by myself if it's possible and straightforward, otherwise I'll be waiting weeks.

By paper underlay, I'm guessing you mean this sort of thing? Or maybe this which is thicker?