How much adhesive is too much adhesive

[djcdan]

First time tiler tying to work out the materials needed.

 

Currently calculating how much adhesive I need and answers on the net are surprisingly inconsistent. Hoping some of the experienced folk here can help.

 

My understanding right now is that you generally use a trowel size a little smaller than the tile thickness itself. So 8mm for 9mm tile or 10mm for 12mm tile etc. On the floor, you'd maybe add a mm or two extra? For large format tiles applied to walls, also add a mm or two?

The floors I have to tile:

2.5sqm 12mm natural stone on backer board

5sqm of 9mm porcelain on backer board

 

All on top of electric UFH, but I don't believe that makes a difference to the adhesive thickness, just to make sure it's flexi enough.

The walls I have to tile:
13sqm of 12mm natural stone - half 200*random (on backer) and the other half 600*300 (on moisture board)

22sqm of large format tiles - 1200*400 (on moisture board)

1.5sqm of feature mosaic (mb)

7.5sqm of 9mm porcelain - 100*400 (mb)

 

Based what I calculated needing for the beds and the coverage rate of adhesive (20kg bag covers 4.5sqm at 3mm bed), I calculated that I'd need around 370kg of adhesive. However, I then thought I would double check on one of these online calculators, which said I'd need only 160kg. I'd rather not be left with ten bags of adhesive at the end of the job, so what is the more accurate answer?

TIA

[Temp]

DIY tiler here..

 

I'm currently using BAL adhesive which is readily available at Topps Tiles. I purchased about half what the calculators said and when I've used that I'll have a better idea how many more I'll need to go pick up. So far their calculator seems to match what I'm using. 

 

Im using the Flex Fibre Plus with a 10mm trowel. That would normally give a 3-4 mm bed but with this adhesive you are also meant to butter the back of the tiles as well which increases the bed to more like 5mm.

 

They seem to have a calculator for each different adhesive. This is the one for the adhesive I'm using.

 

https://www.bal-adhesives.com/products/flex-fibre-plus/#consumptioncalculator

 

It says for 26sqm and a 5mm bed I will need 9 bags or 7 bags for a 4mm bed. I suspect I going to need 8. 

 

I'm laying 600x400x15mm limestone and discovering some is only 13mm thick which is causing a few issues. I choose this adhesive because I work really slow and it stays workable for longer than most.

 

8 bags is 160kg or about the weight of 2 people so not too heavy for the car.

 

Edited March 31, 2022 by Temp

[nod]

7 hours ago, djcdan said:

First time tiler tying to work out the materials needed.

 

Currently calculating how much adhesive I need and answers on the net are surprisingly inconsistent. Hoping some of the experienced folk here can help.

 

My understanding right now is that you generally use a trowel size a little smaller than the tile thickness itself. So 8mm for 9mm tile or 10mm for 12mm tile etc. On the floor, you'd maybe add a mm or two extra? For large format tiles applied to walls, also add a mm or two?

The floors I have to tile:

2.5sqm 12mm natural stone on backer board

5sqm of 9mm porcelain on backer board

 

All on top of electric UFH, but I don't believe that makes a difference to the adhesive thickness, just to make sure it's flexi enough.

The walls I have to tile:
13sqm of 12mm natural stone - half 200*random (on backer) and the other half 600*300 (on moisture board)

22sqm of large format tiles - 1200*400 (on moisture board)

1.5sqm of feature mosaic (mb)

7.5sqm of 9mm porcelain - 100*400 (mb)

 

Based what I calculated needing for the beds and the coverage rate of adhesive (20kg bag covers 4.5sqm at 3mm bed), I calculated that I'd need around 370kg of adhesive. However, I then thought I would double check on one of these online calculators, which said I'd need only 160kg. I'd rather not be left with ten bags of adhesive at the end of the job, so what is the more accurate answer?

TIA

I rarely use anything less than 12 mil 

Usually 15 mil - 18 mil 

 

[Bonner]

1 hour ago, nod said:

I rarely use anything less than 12 mil 

Usually 15 mil - 18 mil 

 

 

Jumping in if I may, as I am planning my tiling ....

Is that 15-18mm finished thickness of adhesive or depth of the notched bed before the tile goes down? How do you apply that much adhesive? I know you back butter the tile (2-3mm?), then is it one layer on the floor? What size trowel (notches) would you use?

[nod]

The thickness of the tile dictates the thickness of the adhesive 

10=10 mil 

You can go as low as 8 mil for walls But they need to be pretty flat 

 

You should alway Bach butter floor tiles I would normally just add just a small amount with the plain side of the float 

[djcdan]

Cheers everyone.

 

7 hours ago, nod said:

The thickness of the tile dictates the thickness of the adhesive 

10=10 mil 

 

14 hours ago, nod said:

I rarely use anything less than 12 mil 

Usually 15 mil - 18 mil 

 

I'm still a little lost about which of these are trowel size and which are bed depths.

 

Is the top quote bed depth and bottom quote trowel size?

 

And so you wouldn't worry about adjusting bed depth to tile size or whether it be on the floor or wall? From what I understood, you're recommending matching bed depth to tile depth, so a 9mm tile would use an 15-18mm trowel to get a 9mm bed depth with bb and a 12mm tile would need a 20mm trowel to get a 12mm bed depth with bb? 

 

20 hours ago, Temp said:

8 bags is 160kg or about the weight of 2 people so not too heavy for the car.

20 hours ago, Temp said:

readily available at Topps Tiles

 

Wouldn't be so much of a problem if the closest Topps (or any other tile retailers) weren't 3 hrs away 🙂. And the local BM's take the piss on materials like this, quite comfortably 50-75% higher than online trade supplies, which results in me shipping a lot of mats in myself.