Laying 18mm solid oak floor on concrete

[Paul-E]

Hi,

We have just had conservatory fitted. I managed to buy 18mm T&G solid oak flooring from Howdens at a good price a while back and am now at the stage where I will soon want to lay it.

Tomorrow I am self levelling the floor but I am not sure how to lay the oak flooring. I would like to do it as cost effective as possible but do not want to have to correct errors at later date so thats reason for my post.....

One chippy has told me to self level floor and fit floor as floating..... putting down a membrane then lay floor on that glueing the T&G leaving 10-15mm expansion gap all around.

However whilst fitting the conservatory the fitters friend turned up who is a chippy and he said to self level then lay sheets of ply screwing to ground at 200-300mm intervals then glue solid floor to ply using flexible glue and not to glue T&G to allow movement also 10-15mm expansion gap.

Tonite reading posts here and elsewhere there seems to be a third option....to self level and glue floor direct to concrete floor without glueing T&G. Some posts say DPC should be used between floor and wood to prevent moisture from concrete affecting glue/floor but I assume that with all correct DPC in place under slab and in walls I should be ok without layer between concrete and solid floor.

I priced glue to glue either direct to concrete or to fixed ply and it is around £120 so the floating floor would be a cheaper option but would it be the right option?

As I will be leaving flooring in conservatory for a week before laying I want to make a decision on how to lay correctly so I can get materials required so any suggestions would be appreciated.

Paul

[eastwood flooring]

[quote="Paul-E"]Hi,

We have just had conservatory fitted. I managed to buy 18mm T&G solid oak flooring from Howdens at a good price a while back and am now at the stage where I will soon want to lay it.

Tomorrow I am self levelling the floor but I am not sure how to lay the oak flooring. I would like to do it as cost effective as possible but do not want to have to correct errors at later date so thats reason for my post.....

One chippy has told me to self level floor and fit floor as floating..... putting down a membrane then lay floor on that glueing the T&G leaving 10-15mm expansion gap all around.

However whilst fitting the conservatory the fitters friend turned up who is a chippy and he said to self level then lay sheets of ply screwing to ground at 200-300mm intervals then glue solid floor to ply using flexible glue and not to glue T&G to allow movement also 10-15mm expansion gap.

Tonite reading posts here and elsewhere there seems to be a third option....to self level and glue floor direct to concrete floor without glueing T&G. Some posts say DPC should be used between floor and wood to prevent moisture from concrete affecting glue/floor but I assume that with all correct DPC in place under slab and in walls I should be ok without layer between concrete and solid floor.

I priced glue to glue either direct to concrete or to fixed ply and it is around £120 so the floating floor would be a cheaper option but would it be the right option?

As I will be leaving flooring in conservatory for a week before laying I want to make a decision on how to lay correctly so I can get materials required so any suggestions would be appreciated.

Paul[/quote]
I would just add that glueing tongue and groove can be iffy. when the wood expands with the seasons the glue can let go and joints will open up.
I would recommend either ply lining or glue direct to the concrete. you wont need to lay a dpm as a new conservatory will have had a heavy sheet laid under the screed. I recommend uzin mk95 about £65 for a 16kg pot that will do 9 square metres. ignore what they tell you on the tin it soaks into the concrete and covers 9m!!! very strong glue no problems and no gaps!

[floorlayergrant]

definatly glue direct to floor screed tongue glueing no good been there done that.

[robbie71]

You probably have the floor down by now but heres my contribution. The way to avoid gaps is to have a low moisture content in the oak which depends on how it was stored over the last few weeks. If you had the house heating on then the planks should have lost most of the moisture that can cause shrinkage hence gaps.
All the methods of laying are ok .
Movement in the floor is ok as long as it all moves together.
A dpm should be laid bearing in mind the concrete slab may still be "drying" a few weeks after laying.