18mm OSB T&G flooring - To glue and leave gap?

StephenS147

The size of sheets are 2400x600mm and with a thickness of 18mm.

I'm resting the boards on joist acoustic tape with the joist centres at 400mm.

Im wondering if there is a gap needed? The sheets are designed that the groove goes all the way in until the two sheets butt tight against each other. I know some sheets have it so that there's a gap when the groove is all the way in.

I'm leaving 2mm here as opposed to 3mm which would be for full sheets. Seeing as these are half sheets I'm going with 2mm plastic spacers. How's that sound?

Also is it really necessary to glue the boards tongue and groove?

Here are some pics.

Calahonda52

Is this a floating floor, with no fixings to the joists?

StephenS147

Calahonda52 wrote: »

Is this a floating floor, with no fixings to the joists?

Screwing it down with 4.5x60 screws.

I've asked a builder friend of mine and he said to glue all the tongue and grooves with wood glue with them butted tight against each other. Seeing as there are expansion gaps around the perimeter it'll be fine to do this.

Here are the screws.

tabby aspreme

Butt together and glue tight, leave the gap at the wall, and drill holes in the osb with a 5mm bit, for the screws.

amber69

They're made to be fitted together tight. 10mm expansion gap around the edges.

Lumen

tabby aspreme wrote: »

drill holes in the osb with a 5mm bit, for the screws.

Those Spax screws don't need pre-drilling.

I appreciate that this is possibly a controversial subject. :pac:

StephenS147

Oh man, a 5mm pilot hole. I'm trying to get rid of a squeaky floor. :eek:

My fear with a pilot hole that size would be that the timber is going up and down on the head creating a squeak after a while. I want the screw threads to bite into the OSB.

the_pen_turner

StephenS147 wrote: »

Oh man, a 5mm pilot hole. I'm trying to get rid of a squeaky floor. :eek:

My fear with a pilot hole that size would be that the timber is going up and down on the head creating a squeak after a while. I want the screw threads to bite into the OSB.

no it will do the oposite. a pilot hole will allow the screw to spin in the osb and allow the head of the screw to pull down the osb. if you just screwed in the osb can create a little lump in between and keep the parts seperated.

StephenS147

I see. I have a habit of putting pressure with my foot beside the screw. But these spax screws have that blank part there for this as Lumen has pointed out. They're absolutely brilliant.