Oak Floor

[beris]

Hi all,

In our Barn conversion we have dug out and replaced all the floors with 150mm reinforced concrete. The ground floor Kitchen and Dining Room has been tiled, the Lounge we are installing an oak floor 25m2. We intend to use 75x50 joists at 400 cnts with the oak boards fixed to them.We have run some vent pipes through the concrete base of the outside canopy into the lounge area to vent the floor. My question is, because the joists are going directly onto the concrete floor, ( we do not have any height to do otherwise) should we put a membrane under each joist, and should the joists be anchored to the base floor. We have only ever installed ground floors in the tradional way on sleeper walls, in the UK, this floor was also to be tiled, but "the powers that be" have decided otherwise.

many thanks

Beris

[powerdesal]

Presumably you laid a membrane under the concrete slab. I am not a builder but I dont remember joists being anchored to sleeper walls so what is the difference in not anchoring them to the concrete. I would personally be considering the joists resting on "packers" at (say) ends plus centre, the packers being anchored to the concrete. The packers would give a small air gap between the concrete and the joist and would eliminate any level discrepancies. Only my own view of course.

[lostinfrance]

[quote user="beris"]

Hi all,

In our Barn conversion we have dug out and replaced all the floors with 150mm reinforced concrete. The ground floor Kitchen and Dining Room has been tiled, the Lounge we are installing an oak floor 25m2. We intend to use 75x50 joists at 400 cnts with the oak boards fixed to them.We have run some vent pipes through the concrete base of the outside canopy into the lounge area to vent the floor. My question is, because the joists are going directly onto the concrete floor, ( we do not have any height to do otherwise) should we put a membrane under each joist, and should the joists be anchored to the base floor. We have only ever installed ground floors in the tradional way on sleeper walls, in the UK, this floor was also to be tiled, but "the powers that be" have decided otherwise.

many thanks

Beris

[/quote]

25m2 the size,but can tell us L x B as it has a bearing on the answer.

[beris]

Hi, thanks for the rely to my question, firstly we did not put a dpm under the floors, because the stone walls are 600mm thick and no dpc, the current thinking is that a dpm would retain and push moisture to the walls and rise up. Leaving it to disapate naturally is what we have done. The idea of the packers will be taken on board.

To the second question, the room size is 5m x 5m.

Many thanks

Beris

[lostinfrance]

[quote user="beris"]

Hi, thanks for the rely to my question, firstly we did not put a dpm under the floors, because the stone walls are 600mm thick and no dpc, the current thinking is that a dpm would retain and push moisture to the walls and rise up. Leaving it to disapate naturally is what we have done. The idea of the packers will be taken on board.

To the second question, the room size is 5m x 5m.

Many thanks

Beris

[/quote]

On the facts above e.g. no DPC  no way would i put a wood floor down. As you say  DISAPATE  NATURALLY  yes under your wood floor.[:(]

[powerdesal]

Given that there is no DPM, I suggest that the packers are waterproof to stop transfer of damp into the joists.

nb. In Wales in a similar situation, I used slate pieces as packers.

[BIG MAC]

There should be a DPM present simple as that.

I would suggest that you bituthene or bitumastic the slab then Install a composite floating insulated floor before fixing oak planks direct to it. Your current scheme will give you a bendy floor in no time flat.

 

 

[Gyn_Paul]

I can't see any reason why you couldn't put a DP membraine down on top of the concrete, ensuring it continues up the sides of the wall far enough to cover the ends of the joists.

Put the joists down, then the boards on top.

p

[BIG MAC]

What I have suggested offers a balanced engineered stable and insulated solution. battens in a subfloor laid out as suggested will not be much cop.

[Fourbarewalls1]

With the regards to your oak floor what type have you gone for, and where did you purchase it from, looking for some ourselves for our first floor area that will measure 70m2

Lee

[Gyn_Paul]

[quote user="BIG MAC"]What I have suggested offers a balanced engineered stable and insulated solution. battens in a subfloor laid out as suggested will not be much cop.[/quote]

"...not much cop "   being one of those technical terms used to confuse the amateurs.!

You're right, of course, the floor does need some insulation,

otherwise it's going to be as cold as.... erm... as cold as...  well let me see now...

as cold as practically every floor in a UK house built before 1985. 

And really, we ought to have progressed a bit beyond that standard.

However, I got the impression from the OP that height was an issue,

so adding a gazzillion cms of insulation may lead to temporal

contusions !

3" x 2"'s are battens ??  not in my world, they're not!

Provided the concrete is flat, and the  3 x 2's are straight, dry, and free of  cranks, twists, and shakes they will support a floor of oak boards perfectly well (esp. if the boards are T&G'd). Cut slabs of 40mm insulation (50mm if you can get it) to fit between the joists.

paul