How Level for Concrete?

[katy1975]

Have just removed old parquet flooring (too damaged to repair) from Victorian house. It was stuck down with bitumen onto concrete. I want to lay solid oak flooring (18mm) in its place. My question is how level does the concrete need to be, in one area there is a slight hump and hairline crack. I have laid a straight board over the area and it does not lie flat. I intend to use combi dpm 3mm under the floor will this help to level? Don't really want to level whole floor and increase the height as want the new flooring to go under the skirting into the gap left from parquet. Skirting is original so cannot easily replace if breaks when removing and it does not take kindly to removing!

 

[alfiembra]

several issues here, what is the intended build up to the new flooring?.

You don't fix the new boards directly to the concrete at the very least you woud lay a vapour barrier (plastic sheeting would do) to prevent any moisture from below affecting the new flooring, this is probably the reason the parquet was laid on bitumen based screed. Then you would construct a floating floor, with is thin battens (maybe 25mm/1" thick) over the vapour barrier with the boarding nailed to the battens. this creates an airspace under the boards and is much easier to level the floor up as the adjustment in level is in the battens. So all in your probably looking at about 40-50mm of depth to build your new floor. Don't know what that means for your skirting boards, if you are careful you should be able to remove them without too much damage.

HTH

Alan

 

[WoodYouLike]

You could use extra underlayment to 'taper-out' the hump (foam underlayment 3mm cut in strips)
And perhaps another solution if the floor doesn't want to go underneath the skirtingboards: leave your expansion gap in front of the skirtingboard and cover the gap later with a flat solid oak beading

 

[katy1975]

Thanks for replies,

Was planning to lay flooring floating? applying adhesive to the tongue and groove- is this not possible?

Hoping there will be enough room to go under skirting parquet was fairly thick- about 2.4cm. Have had bad experiences using beading in the past so wanted to avoid this if possible but will bear this product in mind.

Thanks again

 

[WoodYouLike]

You don't fix the new boards directly to the concrete at the very least you woud lay a vapour barrier (plastic sheeting would do) to prevent any moisture from below affecting the new flooring, this is probably the reason the parquet was laid on bitumen based screed.

Old-fashioned parquet in the UK was always installed with bitumen, nowadays not allowed anymore.
If the unlevelnesses of the concrete floor isn't that much and only on small areas there's no need to install battens (damaging the concrete floor) but can be installed floating, glueing all T&G's correctly. The vapour barrier is part of the combi-underlayment planned to use.

 

[GHFlooring]

check with the flooring manufacturer that the solid wood can be laid floating as alot of solid wood manufacturers dont guarantee the floor if it is laid floating

 

[WoodYouLike]

More and more do state on their instructions it can be installed floating - if appropriate for the floor type - widths smaller than 110mm should not be installed floating.
Manufacturers keep a close eye on the 'market' and preferences of the customer. Floating is becoming more and more popular due to the introduction of the melamine click-systems and the rise in demand for wood-engineered floors over solid. If they only sell solid floors, they have to react to keep their share.

 

[katy1975]

Manufacturers instructions say it can be installed floating but the width is only 90mm- what do you think? Width of the hallway is just over 1m?

 

[WoodYouLike]

We wouldn't install this floating, too narrow boards.
Glueing it down is an option, but for that your underfloor has to be level.