underfloor heating mat in self levelling compound

[Matt123]

I am about to have a go at doing one in my utillity room

I have got a brand new screeded floor 3M x 3M

I have channelled in the flexible conduit for the sensor

I am going to hot glue the mat down

would you recomend mixing the self leveling in one go (25kg bag)
or in 2 or 3 or 4 mixes the bag says it will be workable for 15 to 20 minutes is this enough time to do the floor ?

Matt

 

[Gazzer]

I would put money on one bag wont be enough.

 

[Matt123]

Dont say that

I was about to do it tonight then tile tomorrow

so if it isnt ! can i top it up tomorrow

Matt

 

[Olz]

I dont think one will be enough either, id take a stab at you needing three, any advances....

 

[Matt123]

My heat mat is 4mm thick and the coverage on the bag said 5mm thick would cover 3M square

thats why i got just the one bag I suppose it will have to be done tomorrow now


****

Matt

 

[dagger]

im with oli, 1 bag is no way enough 2 maybe and the third is just in case it dont make it!

if you run out and dont do it in 1 hit you will end up with 2 levels and have to cover the whole thing again! not good

and i am assuming the subfloor is flat and level in the first place!!!

besides you can always take unused bags back right?

ooops for some reason i thought 3m2, just noticed its 9m2 now we are in 4/5 territory!!

i see you three oli and raise you two!!

 

[Time's Ran Out]

My heat mat is 4mm thick and the coverage on the bag said 5mm thick would cover 3M square

thats why i got just the one bag I suppose it will have to be done tomorrow now


****

Matt

1bag = 3sq mts
3bags = 9sq mts
My supplier have a policy of non refund on adhesives, grouts and self levellers as the storage conditions cannot be guaranteed.
Wait till you've gorit all and mix a bag at a time - if you've got a paddle mixer.

Timeless John.

 

[dagger]

on a general avarage i get 1.5/2m2 per 25kg bag over underfloor heating,
but sometimes i have leveled the screed to get it flat and level before laying the heatmat.

you want the minimum amount of self level to cover the wire, if you bury it too deeply it will be much less efficient and cost you more money in the end.

but thats just me!

 

[Gazzer]

And watchout for the mat floating to the surface. try priming the floor before laying the mat to help the self adhesive strips on the mat (if you have that type) stick.

 

[dagger]

1bag = 3sq mts
3bags = 9sq mts
My supplier have a policy of non refund on adhesives, grouts and self levellers as the storage conditions cannot be guaranteed.
Wait till you've gorit all and mix a bag at a time - if you've got a paddle mixer.

Timeless John.

that is a bit harsh of your supplier john, you would proberbly return it the next day or even the same day as it wont take long to pour it!

and yes a paddle mixer is essential, 1 bag at a time and pour, if it dont make it another bag and pour etc.

 

[DHTiling]

When you say brand new screed...how new..?

 

[Matt123]

And watchout for the mat floating to the surface. try priming the floor before laying the mat to help the self adhesive strips on the mat (if you have that type) stick.

Hi
The mat is glued down flat to brand new screeded floor gotta go back to jewsons then in the morning to get more bags

Matt

 

[Matt123]

When you say brand new screed...how new..?

Monday it was put down

Matt

 

[DHTiling]

You have issues then...

 

[Matt123]

You have issues then...

I'll have more than issues if this floor isnt finished this weekend
D-I-V-O-R-C-E by tammy wynette comes to mind

 

[Gazzer]

Hi
The mat is glued down flat to brand new screeded floor gotta go back to jewsons then in the morning to get more bags

Matt

WOOOOAAAAAAA Stop there ! This SLC you have is it suitable for UFH ?


Oh and you need to let the screed dry properly.

 

[dagger]

1mm per day of screed drying time!! 60mm = 60 days!!!!!!!!!

 

[Matt123]

Adhesives and Sealants for the DIY, Trade & Stationery Markets

It says on the bag "suitable for under floor Heating

Matt

 

[Gazzer]

1mm per day of screed drying time!! 60mm = 60 days!!!!!!!!!

Or 1 day per 1mm of screed :lol:

 

[Matt123]

Just gets better and better

so my dishwasher washing m/c and tumble dryer will have to come in from under the gazebo on the patio where they have been while the extension was being built
sit on the screed for 60 days while i wait for the screed to dry then kick it all out again in november to do this job
while saving up to get a proper tiler in to do it

what will it cost me to do a 3meter squre utility room
I already have the tiles

Matt

 

[DHTiling]

You can of course use an un-coupling membrane...first then put the ufh on that...

SUITABLE SUBSTRATES FOR SCHLÜTER-DITRA:


It must be verified that substrates which are to receive the Schlüter-DITRA matting are even, load bearing, clean, and compatible. Bond inhibiting surfaces must be removed. Any unevenness or height and slope differences in the substrate must be levelled prior to the application of Schlüter-DITRA.

Concrete
Concrete is subject to lengthy deformation processes due to shrinkage. Concrete and pre-stressed concrete may build up tension because of deflection. Schlüter-DITRA absorbs inherent stresses between the concrete and tile covering so that the tile can be installed as soon as the concrete is hard enough to be walked upon.

Mortar screeds
According to the applicable standards, mortar screeds must cure a minimum of 28 days prior to the installation of tile, and their residual moisture content must be below 2% (percentage by volume). In particular, floating screeds and heated screeds tend to change shape or develop cracks after installation, e.g. due to load stresses or temperature changes. With Schlüter-DITRA, tiles can be installed as soon as the screed can be walked upon.


Schlüter-DITRA is also recommended for uncoupling of radiant heated floors consisting of thin electric heating mats. Schlüter-DITRA may be installed either above or below the heating mat. However, the uncoupling function is more effective if Schlüter-DITRA is installed above the heating mat.

Schlüter-DITRA - Schlüter-Systems

 

[dagger]

is it 3m2 or is it 3m x 3m

there is a BIG difference!

3m x 3m = 9m2

1m x 3m = 3m2

 

[dagger]

Or 1 day per 1mm of screed :lol:

no, one day per mm......english is my first and only language, and i steel cant speak it!:lol::lol::lol::lol:

and i am worst at tipping!

 

[jay]

lucky you asked the question on tf or you would of been up the creek:8:

 

[Matt123]

is it 3m2 or is it 3m x 3m

there is a BIG difference!

3m x 3m = 9m2

1m x 3m = 3m2

3M x 3M

Matt

 

[faithhealer]

hi matt sorry you are hearing what you wanted to hear but these lads know their stuff.
No one has mentioned insulation boards yet. Ufh heating mats straight onto a concrete floor end up being too expensive to run!!
had a customer who wanted it doing immediatley, told her to wait until dry, (despite inconvenience to her) fitted insulation boards etc. She was delighted and has now forgotten about the 'waiting time' Do it right Matt and your wife will appreciate it in the long run even though you might get ear ache this week end.

 

[Matt123]

Cheers

How thin are these insulation boards ?

Matt

 

[Matt123]

lucky you asked the question on tf or you would of been up the creek:8:

Too right :smilewinkgrin:

At least I got the time to sort it out now and not rushed

Matt

 

[faithhealer]

Cheers

How thin are these insulation boards ?

Matt

I would use 10mm
Underfloor Heating | Floor Insulation | Uheat

Give UHeat a ring, (Sponsors) or pm Pete tilersforums.com | Tile Forums | Tiling Forum - View Profile: pjrich

 

[mags]

Do these boards negate the necessity of plying a wooden floor? I hope so or youll end up touching the ceiling.