Hardiebacker, do I screw down after addy has set?

[Bathfix Bob]

Sorry guys, I had a quick search, I'm doing some work in my current bathroom today and its time to screw the 6mm Hardiebacker boards down.

Never used these on the floor until now (always use them from now on) I would like to know the correct procedure.

6mm trowel?

Primer?

Plasterboard screws okay?



Do I leave it till tomorrow and screw down or do I screw down as soon as I've seated them on my addy (extended set).

Cheers guys, I'm going at 10:20 so advise would be great

[merlecollins]

I normally use a 4 or 6mm serator when fixing HBB and mix the adhesive slightly softer than if fiixing tiles.

Cut all the boards and lie them in dry to make sure they all fit OK, leaving a 3mm gap between boards. Lift them all and spread your adhesive for the fiorst row.

Bed the first row of boards in and screw down straight away at 200mm between screws.

Repeat as above, until floor is finished.

When set, I would go back cut self adhesive fibre tape to the joints and then with the flat side of your serator, smooth the same SPF adhesive into the joints, covering the tape as you go - make sure to leave them nice and flat.

Then, when done, get a nice cup of tea.

[timeless john]

Screw it into the wet fast set flexible grey adhesive.



Then I'd have a coffee!

[Bathfix Bob]

Cheers guys,

As there are only 2 full boards down and a bit of a cut one and I'm not tiling till tomorrow, can I use my extended set and save my rapid for the tiles?

Sub floor is 18mm WBP scewed and glued to joists, solid as heck.

[Stewart]

Pretty much as above.

Cut boards to size and lay dry with a 2mm gap all around the board.



Use use 6mm trowel with slightly wetter adhesive.



Fix down boards with a suitable screw at 200mm apart (28 screws per sheet)



Tape joints with a suitable fibre tape to use with cement based adhesive and I normally flush the tape as I fix the tiles.



I use no more ply which is basically the same and I always give it two coats of sbr in the workshop as I get it by the pallet and is something for the apprentice to do on a quiet day.

[Del W]

For a small area like yours it is only going to use a small amount of rapid.Then you can walk on it 1st thing Monday without worry.

[Bathfix Bob]

Okay I'll use my rapid, cheers guys.

[grumpygrouter]

The adhseive is there as a void filler only not as a "glue" it is the screws that hold it in place so you could actually tile on it straight away if you wanted.