Cold flooring in extension

[TryC]

Hi All,

 

Looking for some advice please.  We had an extension installed and this past few weeks, I have noticed the floors to be SUPER cold, despite being told this room would be the hottest in the summer (I know, we're not in summer), but I didn't expect the extension to be the coldest during the cold season. 

 

Anyway, the walls. I had asked this when it was built, why there was a gap from the wall and floor and I was told this was normal and it was for the wall to breathe, and for damp not to rise. 

 

They cut out a spot for the water pipes/sinks in a shape of a square. Once the kitchen was installed, the square basically has the pipes but it is...I don't know the right word but it is not filled in or insulated at all, it is essentially the pipe in the square hole.

 

I have noticed the floor (LVT) to br extremely cold when walking on it. It just feels so sold. I usually wear slippers and never noticed it until I was in my socks to get something quickly.

 

I think the cold is coming frome the square hole, not only that the gaps i was told was normal....(I am beginning to think is not right?)

 

Not the extension is on a suspension floor.

 

Any advice is appreciated.

[bmj1]

The fact that the whole floor feels cold suggests to me that you UFH itself isn't working as expected (I'm not worried about the gaps or hole right now - these issues feel secondary to me - let's get the floor heating up first). I've spent a bunch of time working on my UFH to get all 3 floors behaving correctly...

 

A few questions for more context:

 

(1) Flow temp of UFH

What is the flow temperature of your UFH ?

 

(2) What temperature is the floor itself reading ? Measure it in a few places

You might want to use a thermostatic gun (https://www.amazon.co.uk/ABOHU-Thermometer-Temperature-Non-Contact-Measuring/dp/B0FGDBH472) - be sure to set the EMS (emissivity) to 0.92 to get an accurate reading 

 

(3) Has the UFH been commissioned correctly? I.e. actuators adjusted for flow rates and balanced

 

Further context on your sub-floor build up

(4) Insulation

How much insulation is underneath the floor ? What material and how deep ? (e.g. PIR at 200mm)

 

(5) Screed

What screed did you use and how thick is it ? (e.g. sand/cement at 80mm)

[Russell griffiths]

   @bmj1 who said it had ufh.
 

What’s the floor make up

what insulation is under it ?

what was on the drawings ?

what was actually fitted ?

do you have any pics. 
 

I bet it’s a suspended timber floor with very little insulation. 

Edited Wednesday at 14:30 by Russell griffiths

[TryC]

Apologies, and thanks for the speedy reply. I do not have underfloor heating if UFH is what that stands for. It is suspended floorboards over concrete, then on the wooden things there are the thick insulation boards (celotox)? Then cabersheild i think it is called, screed then the LVT floor.

 

I would say the floor feels absolutely coldest in front of the sink (the immediate area near the square hole) than the rest of the room on the right (not in the photo).

[Russell griffiths]

Reading your reply now I think you have just had the misfortune to appoint a shit builder with poor understanding of insulation and airtightness. 
this is going to be extremely hard to fix without ripping a lot of stuff out. 
 

does it feel cold or is it more a draft, you could try taking the kick boards off the cupboard and see if that pipe hole is allowing a cold draft in. 

[TryC]

Hi Russell, it defo feels like the air is coming up from that hole. I did ask a plumber if I could fill it. He said yes, but then I was thinking I don't know what or how. Expanding foam seems like an idea or a bad on or even the steel wool (not for air i guess but insects) but it am not sure if steel wool is a fire hazard.

 

 

I just feels like im standing on ice near the area of the square hole.

[ProDave]

Get all the kick boards off and go around the whole room perimiter with a can of spray foam and fill the gap between the walls and floor especially where the drain pipe goes down.

 

It sounds like there is insulation under the floor boarding, but the (sadly usual) lack of attention means there are likely to be cold draughts getting in from almost anywhere between the wall to floor junction.

[TryC]

It will not damage the pipes will it? 😞

[Russell griffiths]

4 hours ago, TryC said:

It will not damage the pipes will it? 😞

Buy a couple of cans of illbruck 330 airtight foam, you will need a gun to go with it, so two cans of foam and a gun will set you back £40, but trying to lay on your belly with your arm under the cupboard and use the diy can of foam will be something to see. 

[saveasteading]

 More questions.

How recently was this built? The plaster looks damp still, and perhaps the floor too.

How thick do you think the celotex is?

Is there a space between concrete on the ground, and the timber floor?

Is there any heating in the room?

 

For an immediate benefit, stuff the draughty hole with rags: it will be a good test before doing it permanently.

Edited Wednesday at 20:17 by saveasteading

[Andehh]

Go to screwfix, ask for 4 cans of expanding foam, and an expanding foam gun. 

 

Screw the can onto the gun, and pull the trigger in your garden to get an idea of the flow and how it expands etc. 

 

It's horribly sticky stuff, so don't get too carried away. 

 

All holes, gaps, areas you feel air could be coming in... Squirt deep into it and slowly pull the nozzle out. 

 

It will expand out, but it is very easy to cut back with an old stake knife 24 hours later. 

 

It's messy stuff!! YouTube videos will give you a good idea of what you want to achieve.

 

That will resolve air movement. 

 

Or... Ask the builder to do this, it's a 15minute job. 

 

 

________________________

 

Before you panic about the quality of install, how old is the rest of the house? Whilst the extension is highly unlikely to meet the HIGH expected standards of Build hub (we're all home building nerds!!!), modern building regs for an extension are better then a house a few decades old... So all needs to be viewed proportionally.

Edited Wednesday at 22:20 by Andehh

[Redbeard]

Can I suggest you use Illbruck FM330 air-tight foam? Pretty well all foam will help, but not all is air-tight, nor dries as flexible as FM330. More expensive, but just better.