What tape to use in slc?

[Bob2]

Hi all. I have 40sqm of floor to pour slc over. Half is concrete and half is 25mm plywood over new solid joists. Where they meet at the join...it is pretty near level but concrete does dip by about 8mm at one area. I am using Mapei Ultraplan as it is fibre reinforced and was also recommended to me.

Please can someone advise if I should be taping the join where the substrates meet with a tape of some sort? If so....what type of tape? Would a normal scrim tape suffice? This is a big area for me to get wrong hence why I'm asking for your help.
Thanks people.

 

[Steve6690]

The ply and concrete will expand/contract with changes in temperature so I'd have thought an expansion gap/trim at the join would be required rather than taping the two together.

 

[Dave]

Yep , needs an expansion joint at that transition in substrates.

 

[Bob2]

The ply and concrete will expand/contract with changes in temperature so I'd have thought an expansion gap/trim at the join would be required rather than taping the two together.

Hi..thanks for reply. Is a fibre tape no good within the levelling compound? I'm putting engineered wood floor over the top not tiles. Thanks
[automerge]1592147169[/automerge]

Yep , needs an expansion joint at that transition in substrates.

Hi...I thought I'd replied to both then....question as above Dave...and also....could I use caulk in the joins before I level? Thsnks

 

[Steve6690]

Tape is fine to use with slc over the top. I'd assumed you were tiling the floor hence my suggesting expansion gap. I have no idea if you'd need one with engineered wood floor but I suspect you do.

 

[Bob2]

Tape is fine to use with slc over the top. I'd assumed you were tiling the floor hence my suggesting expansion gap. I have no idea if you'd need one with engineered wood floor but I suspect you do.

Thanks Steve....what tape would you say would be my best chance? A fibre tape like you use with backer board is what I'm thinking at the moment. The wood floor will be a floating floor with underlay so just want to give it the best chance of limiting cracks. Do you think I should caulk all the gaps between plywood.....and between plywood and concrete? Would leveller be ok over that after the primer? Thanks.

 

[Steve6690]

I have to be honest and say I've no experience of wood flooring but I'm sure someone on here can give proper advice. I'd hate to steer you wrong.

 

[Dave]

Hi..thanks for reply. Is a fibre tape no good within the levelling compound? I'm putting engineered wood floor over the top not tiles. Thanks
[automerge]1592147169[/automerge]

Hi...I thought I'd replied to both then....question as above Dave...and also....could I use caulk in the joins before I level? Thsnks

Glued joints and floating will be fine.

 

[Bob2]

Glued joints and floating will be fine.

Thanks Dave, but can I use a fibreglass tape over the concrete/plywood join before I pour the self leveller? I do need to put the leveller down...I just need to know if I'm better with the tape or just pour the leveller without anything over the join? Cheers.
[automerge]1592160556[/automerge]

I have to be honest and say I've no experience of wood flooring but I'm sure someone on here can give proper advice. I'd hate to steer you wrong.

That's ok Steve...I appreciate your advice...thanks.

 

[Dave]

Thanks Dave, but can I use a fibreglass tape over the concrete/plywood join before I pour the self leveller? I do need to put the leveller down...I just need to know if I'm better with the tape or just pour the leveller without anything over the join? Cheers.
[automerge]1592160556[/automerge]

That's ok Steve...I appreciate your advice...thanks.

If the timber flour is floating, then no beed to tape the joint , just Silicon it to stop leveller flowing down the joint

 

[Bob2]

If the timber flour is floating, then no beed to tape the joint , just Silicon it to stop leveller flowing down the joint

Thank you Dave. One last question...If I did use a fibreglass mesh tape for belt and braces...would it be ok within the leveller? Thanks.

 

[Dave]

Thank you Dave. One last question...If I did use a fibreglass mesh tape for belt and braces...would it be ok within the leveller? Thanks.

Yes