Insulating cold kitchen floor (limited by floor height)

[boger]

Hi All,

I have a concrete kitchen floor (house built in 2005) with tiles on top and our kitchen is very cold in winter (when left a thermometer on the floor overnight it showed 8 deg), so quite often our kitchen temp drops to 15/16 deg in the morning (thermostat is set to 20 overnight and is located on the 1st floor), therefore heating needs to run every morning to heat the kitchen up.

 

What I was thinking, limited by floor height, is to remove all tiles (this gives extra 12 - 15mm) and use:

• 25mm Thermafloor TF70 PIR Insulation Board Kingspan or 25mm Kingspan Kooltherm K103 Floorboard (their technical team told me this one is not suitable for this application)

• 2x – 6mm SP101 Plywood

• 2.5mm glue on LVT

So in total about 40mm.

 

I have few questions to the above:

• Is it an option to go to, are there any better options?

• Can plywood be replaced with 2x 6mm HardieBacker?

• Would only Fastwarm 30mm Tile Backer Insulation Board or wedi Tile Backer Board + 10mm self-levelling + and LVT on top work?

• Any solution needs to be able to support kitchen furniture and appliances (washing machine is my biggest worry, due to vibration and movement)

 

What I’m trying to achieve is as much insulation as thin as possible, hope it makes sense.

Thank you for any help.

 

[elite]

I'd probably go with a tile backer with SLC - marmox claim 40 tonnes / m2 when tiled, not sure about LVT. They say you can use any thickness  board, unless onto floorboards which then has to be minimum of 10mm. So thickness really depends on how much insulation you want vs how much height you want to lose

 

You probably only need 3mm SLC, unless the floor isn't level

 

A much more painful option would be to dig down and get a decent amount in the slab

[JohnMo]

PIR is about 12 to 14Te m² (120 to 140kPa)

 

Thread here

https://forum.buildhub.org.uk/topic/32633-curiosity-how-can-celotex-insulation-hold-the-weight-of-the-screed-floor-units-people/

[Nickfromwales]

 

1 hour ago, boger said:

Hi All,

 

I have a concrete kitchen floor (house built in 2005) with tiles on top and our kitchen is very cold in winter (when left a thermometer on the floor overnight it showed 8 deg), so quite often our kitchen temp drops to 15/16 deg in the morning (thermostat is set to 20 overnight and is located on the 1st floor), therefore heating needs to run every morning to heat the kitchen up.

 

 

 

What I was thinking, limited by floor height, is to remove all tiles (this gives extra 12 - 15mm) and use:

 

• 25mm Thermafloor TF70 PIR Insulation Board Kingspan or 25mm Kingspan Kooltherm K103 Floorboard (their technical team told me this one is not suitable for this application)

   

• 2x – 6mm SP101 Plywood

   

• 2.5mm glue on LVT

   

So in total about 40mm.

 

 

 

I have few questions to the above:

 

• Is it an option to go to, are there any better options?

   

• Can plywood be replaced with 2x 6mm HardieBacker?

   

• Would only Fastwarm 30mm Tile Backer Insulation Board or wedi Tile Backer Board + 10mm self-levelling + and LVT on top work?

   

• Any solution needs to be able to support kitchen furniture and appliances (washing machine is my biggest worry, due to vibration and movement)

   

 

 

What I’m trying to achieve is as much insulation as thin as possible, hope it makes sense.

 

 

Thank you for any help.

 

You'll be able to set the Wedi boards down with flexible tile adhesive, as these need to be fixed in this scenario. There are cheaper equivalent boards available online btw.

 

You can do the 10mm SLC (Mapei builders screed with fibres prob best here), and you're off to the races. For belt and braces I'd add a mesh (this type of thing LINK ) into the pour, and then your LVT.

 

Also, consider adding an electric UFH mat whilst you're there, and maybe just for winter set that to the minimum cold temp you want the floor to be in the mornings, set to say 17-18^oC and timed to turn on at 07:00 and off at 09:00; on and off with UFH controllers are actually times and temps, so you can choose comfort and economy temps for different times of the day.

[boger]

Thank you for all the suggestions, much appreciated.

 

As I will be doing it myself and not a builder, could you please suggest a reasonable materials. I'd rather pay more for better quality then regret later.

 

Would the below be ok (ordered by layers):
Concrete + ARDEX P 51 Primer
MICROTEC® Flexible Standard Set Tile Adhesive - ARDEX X 77
Fastwarm 30mm Tile Backer Insulation Board (picked this one as Thermal Conductivity: 0.027 W/mk, others like Marmox Multiboard have 0.034)
ARDEX P 51 Primer
Fastwarm 150W Electric Underfloor Heating Mat Kit - this is just an example need to read more about it and decide which one to use
ARDEX K 40 HB or Mapei Ultraplan Renovation Screed 3240 + Bond It Resistant Glass Fibre Woven Render Reinforcing Monster Mesh 
Styccobond F48 PLUS + LVT

 

Thank you for any suggestions and/or comments.

 

 

 

[Nickfromwales]

1 hour ago, boger said:

Thank you for all the suggestions, much appreciated.

 

As I will be doing it myself and not a builder, could you please suggest a reasonable materials. I'd rather pay more for better quality then regret later.

 

Would the below be ok (ordered by layers):
Concrete + ARDEX P 51 Primer
MICROTEC® Flexible Standard Set Tile Adhesive - ARDEX X 77
Fastwarm 30mm Tile Backer Insulation Board (picked this one as Thermal Conductivity: 0.027 W/mk, others like Marmox Multiboard have 0.034)
ARDEX P 51 Primer
Fastwarm 150W Electric Underfloor Heating Mat Kit - this is just an example need to read more about it and decide which one to use
ARDEX K 40 HB or Mapei Ultraplan Renovation Screed 3240 + Bond It Resistant Glass Fibre Woven Render Reinforcing Monster Mesh 
Styccobond F48 PLUS + LVT

 

Thank you for any suggestions and/or comments.

 

 

 

Looks good to me. 
 

When your ready to pour the SLC bump the thread and we’ll give you some pointers to make that as simple as possible.