Make life easy, search the forum.

Discuss *Advice needed on under tile surface NEWBIE* in the Tiling Advice | Tile Forum area at TilersForums. USA and UK Tiling Forum

United States of America
T

Tile_novice

Please checkout the following advertisement.
Hello all,

First and foremost I would like to thank all those that have contributed to these forums for providing their wisdom.

To give you some background, Im currently doing some DIY in the house (took on a bit more then I could chew!).

Our floor was constructed on the old wooden 9 x 2 floor joists which had considerable movement leading to our tiles cracking over time so I decided to do a proper job and remove the floor boards, put boards under joists, followed by 50mm insulation, wet underfloor heating then a final 50mm layer of screed. I was hopeful this would make the floor more structurally sound causing less movement in the floor, ultimately eliminating the cracking.

So now screed is done and drying, I have been researching on the options going forward - I originally was going to do T&G floor, followed by concrete backing board then the tiles. I was advised against the T&G as the surface would not adhere well to the backing board and it wouldn't be as structurally sound as plywood.

So now my plan at present would be 2.4m x 1.2m 18mm plywood (have contemplated 25mm to make the floor more solid but thought it may be a bit overkill?) then the concrete backer board, then the tiles (marble).

Any advice on the above would be really really appreciated.

Thank you for taking the time to read this
 
OP
T

Tile_novice

Use fermacell gypsum flooring. Done lots over that type of floor with no problems
Can that be used straight on the screed layer? The main reason for us using a wood layer on top of the screed was for stability, as well as lifting the floor height to match the existing kitchen (higher then the Hall/front room area I’m doing). Considering the long joist length underneath what thickness gypsum (fibreboard I’m assuming?) would you recommend using?
Thanks very much for your time
 

Chalker

TF
Arms
Reaction score
628
It’s 25mm thick and as long as your floor will not flex, it will not move.
Will also help the underfloor heating, as is has mass.
For tiling, after fitting the floor. You can tile straight onto it. Sweep, vacuum and then use a gypsum based adhesive.
 
OP
T

Tile_novice

It’s 25mm thick and as long as your floor will not flex, it will not move.
Will also help the underfloor heating, as is has mass.
For tile, after fitting the floor. You can tile straight onto it. Sweep, vacuum and then use a gypsum based https://www.tilersforums.com/forums/tile-adhesive/.
Many thanks for that - my only concern is the potential movement of the floor underneath (as joists are long) but I'm assuming the 50mm screed between would have significantly strengthened the floor.
I'm going to research the gypsum floor you have recommended thanks for your help
 
OP
D

Dumbo

Many thanks for that - my only concern is the potential movement of the floor underneath (as joists are long) but I'm assuming the 50mm screed between would have significantly strengthened the floor.
I'm going to research the gypsum floor you have recommended thanks for your help
I'm not sure about that . Your joists weren't designed to carry an extra 85 kilos per square metre static load .
 
OP
T

Tile_novice

I'm not sure about that . Your joists weren't designed to carry an extra 85 kilos per square metre static load .
That was also a concern of mine - I initially was going to double up the joists to strengthen it because these joist lengths aren't used in modern day construction. My biggest fear was the floor completely collapsing, however with the screed done in 1 pour I assumed (maybe naively) that the load would be spread uniformly. As you said the additional static weight is substantial. You are triggering my anxious nature lol!
 

Reply to *Advice needed on under tile surface NEWBIE* in the Tiling Advice | Tile Forum area at TilersForums.com

Or checkout our tile training advice or the Tile Standards

This website is hosted and managed by www.untoldmedia.co.uk. Creating content since 2001.
Please visit our sponsor websites, they keep the forum free to use!

New Tiling Questions

UK Tiling Forum Stats

Threads
66,601
Messages
866,709
Members
9,513
Latest member
05jtaylor
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock