SLC on plywood

[pickles88]

I have screwed some 9mm ply over floorboards. I want to use SLC to make it more level before installing a floating engineered floor. I have some primer I am going to go out and get the flexible Mapei Ultraplan Renovation SLC. I have two questions:

- what is the best way of sealing the gap between the edge of the plywood and the wall where the skirting board was? Should I use some ply offcuts and tape them to wall and caulk where it meets the floor and do I need to caulk between the ply joints where the sheets are butted?

- The room is c. 28sqm. Is it wise to attempt to do the whole room or should I just be doing the dips and the bits that run off the most? I am worried if I don't do it and just put the underlay/flooring down then I will get annoyed by it eventually.

Thanks all

 

[Mr Chibs]

I've just used this, it's very good on plywood, (no cracks) doesn't go as far as you think, so I'd do the dips first, then cover the whole lot if needed.
Mix as instruction ratio, but next time I think I would add a little more water just to make it a little easier to pour.

My floor was out 20mm in one corner and 4mm in the other. I used it my my bathroom 2.5x2m and just used tape all the way round first.

No need to caulk between the boards.

PS I used 12.5mm ply.

 

[pickles88]

How did you move it around? I was looking at getting a spiked roller. Did you use the primer that Mapei recommend? I could not get my hands on it so I got Setcrete High Performance Floor Levelling Acrylic Primer. Have you used this before also? I am concerned it could dry too quickly and then crack, especially given it is quite warm outside (and therefore inside) at the moment. Did you start to pour your mix from the high part and move it down to the lower part, or just pour it in the lower part? Thanks!

 

[Mr Chibs]

I just used a plastering trowel. I didn't bother with the spiked roller.

This is the primer I used:
https://www.wickes.co.uk/Norcros-Mu...&utm_content=deeplink&utm_campaign=DIYnot.com

I started in low point, only because I had to work back to the door, being a bathroom.
I wouldn't worry about the curing time, leave overnight, and it's as tough as anything the next day.

Have a spare 500ml/litre of water ready when you mix, you might need a bit more, as previously mentioned.

I wouldn't mix more than a bag at a time if working on your own, I had to lug it all upstairs in trug, it's heavy when mixed!

hth