Extension doesn’t stay warm

JoeLowe

I bought a new house a few years ago and have issues with the kitchen extension retaining heat. (Was added by the previous owners in 2010)

The room is north facing, but just not retain heat.

I have replaced the French doors, blocked up a side door and have changed the windows but can’t get the room to remain warm.

The extension does has a high ceiling with two large velux windows.

Considering if I need to get a heat loss report carried out.

Thought on solutions are welcome.

grumbler

It can be that heating just isn't sufficient for a big glass door and several windows.

Jeepers_Creepers

Do you know if it had proper plans drawn up and BCO oversight? Have a look at 'Planning' on your LA's website - enter your postcode.

Does it look and feel well built? Do you know which builder was used? (Their reputation should give a good indication of its quality).

Most likely, I think, it's as Grumb says - it just hasn't had enough heating factored in. What does it have?

FreeBear

Thermal imaging camera to see where the heat loss is. Then expect to spend quite a bit on insulation, plastering, and general redecoration - If the insulation levels are good, it may just be a case of a bigger radiator.

JoeLowe

grumbler said:

It can be that heating just isn't sufficient for a big glass door and several windows.

I can get the warm room, it’s just that it disappears as soon as the heating is turned off. 

JoeLowe

Jeepers_Creepers said:

Do you know if it had proper plans drawn up and BCO oversight? Have a look at 'Planning' on your LA's website - enter your postcode.

Does it look and feel well built? Do you know which builder was used? (Their reputation should give a good indication of its quality).

Most likely, I think, it's as Grumb says - it just hasn't had enough heating factored in. What does it have?

I can get the room warm, just can’t keep it warm. 

The previous owner has given me the sketches for the extension, but haven’t seen the signed off plans.

JoeLowe

This is the extension. 

tacpot12

If the room cools down quickly it means it has very little thermal mass - the floor, and to a lesser extent the walls are your source of thermal mass. If you don't heat the floor for long enough or if it doesn't have much thermal mass, you will find the room cools down quickly. You need a thermally massive floor, and you need a way to get heat into the floor. Ideally the floor would be 8-9 inches of concrete with underfloor heating set into it (and 9 inches of XPS foam under the concrete). 

Also, the roof isn't thick enough to have a great level of insulation, and it has two very large glass windows, along with all the  other glass in the room. 

There is a problem in the UK that many builders and home owners think that if they build to the building regulations they are going to have a warm, efficient home, but this isn't so because the regulations are just not that rigorous.  The Passivhaus standard has taken off because it can deliver warm, efficient homes, but the design needed to achieve it is way in excess of the current UK building regs. for refurbishments.

It would seem that the room has been built to be thermally responsive, i.e. it has little thermal mass, but enough insulation to retain some heat. So it will need to be heated constantly to replace the heat lost via the walls, roof, windows and into the rest of the house. I would put the heating on when you want the room to be warm, and don't worry about the fact that it is cold when you are not in.

grumbler

JoeLowe said:

grumbler said:

It can be that heating just isn't sufficient for a big glass door and several windows.

I can get the warm room, it’s just that it disappears as soon as the heating is turned off. 

JoeLowe said:

This is the extension. 

What do you expect with such huge proportion of glass in a small room? I wouldn't be surprised if it doesn't meet the current regulations in this respect.

JoeLowe

That’s only the extension was in the photo. The room is much larger.

As mentioned above, the extension was built before we moved in and we have already blocked up another door way in the room.

Is there anything we can do to the roof space? Remove the velux windows??? / change the roof tiles to ones that insulate better? / add better insulation into the roof?

Doozergirl

JoeLowe said:

That’s only the extension was in the photo. The room is much larger.

As mentioned above, the extension was built before we moved in and we have already blocked up another door way in the room.

Is there anything we can do to the roof space? Remove the velux windows??? / change the roof tiles to ones that insulate better? / add better insulation into the roof?

You really could do with the thermal imaging camera, otherwise you're just poking around without really knowing where the issue is.  It could be entirely missing in insulation, for all we know.  Was the extension signed off by building control? 

 The camera will pinpoint areas immediately.   

Of course, blocking up windows, making them smaller or seeing if newer ones are more efficient is an option, but there might be a more fundamental issue that allows you to keep the light that you currently enjoy.