Why is one of my rooms so cold?

twopenny

What direction is that corner of the house facing?
North or east facing rooms are always cooler than south facing ones. Useful in a heatwave. Need more attention if you want to sit there in winter.
The draught under the door should let warm air in and help ventilate.
The mould in a corner possibly the coolest spott where heating isn't reaching -or check the outside for damage to mortar. 
Yes, I'd get the carpet up and seal between floorboards and especially where skirting meets fo the floor. This is a great draw for cold air.
Then get a good underlay. There are some good ones now. The carpet sound reminds me of the old cheap foam underlay which used to dry to crunchyness. You will find a powder leftwhich will need vacuuming up then a damp sponge to get rid of.
Once you've done the floor you should find it makes a huge difference. If it doesn't then look at the windows.

aoleks

first, a couple of things...

1. you said you had mould in one of the corners. top corner or bottom corner? corner on an external or internal wall?

2. mould signals the presence of humidity or damp for a longer period of time, so where there's mould, there's an issue.

3. condensation is normally evenly spread and in most cases, focused on the windows. the fact that you have it on the flood/ceiling/wall, tells me there's a cold patch in the house.

4. if it's a top corner (ceiling), then most likely there's a problem in the loft. go in the loft, check everything above the mould spot. missing insulation? leak?

5. if it's a bottom corner (floor), check the outside wall. any sign of damage? missing bricks? gaps? missing cavity insulation? leak?

that internal door has nothing to do with your cold patch, radiator seems fine too.

Grenage

What's the point in sealing between the floorboards when underlay and carpet are going on top?  That seems like a monumental waste of time

Bendy_House

Grenage said:

What's the point in sealing between the floorboards when underlay and carpet are going on top?  That seems like a monumental waste of time

The combined seepage of many many metres of loose joints, can add up to more than a soupçon of wind.

Are you certain that even 'rubber' underlay ain't percolateabubble?

But, yes, the perimeter around - and under -the skirtings is the biggie.

FreeBear

Grenage said:

What's the point in sealing between the floorboards when underlay and carpet are going on top?  That seems like a monumental waste of time

Gripper rods are fixed to the floor leaving a gap of 6-8mm between them and the wall/skirting. The underlay then goes down and is trimmed to fit inside the gripper rods. When the carpet is stretched & laid, the edge is pushed down into the gap between gripper rods & wall/skirting. Whilst this will reduce the draughts coming up from any gap under the skirting, it doesn't hurt to plug the gap and be done with it.

Using expanding foam and a gun, it doesn't take very long to lay down a thin bead - Could probably do a mid sized room in 15-20 mins. Poking a strip of foam (draught excluder ?) with a filling knife might take an hour.

NSG666

Did you get to the bottom of the damp issues from your previous post?

Is this damp? — MoneySavingExpert Forum

Brie

It's not just the location of the room in the house but what's outside too.  Our kitchen windows face south/south east as do our lounge.  The lounge can be nicely warm by mid morning, in the summer just from the sun.  The kitchen remains quite cool and is down right cold in the winter.  The difference is that the sun come up and the kitchen is shaded until at least mid morning due to a  honking large tree in the neighbour's garden.  This works out quite nicely for us as it means we have a couple of cupboards that remain cool so are good for storage.

coffeehound

Can you post a photo of the outside wall(s), @VT41

VT41

Will try and respond to all queries here - appreciate the response all. 

It's a first floor flat in a Victorian conversion. Spoken to the owner of the flat above who doesn't have any leaks.  She mentioned she also had a dehumidifer RE moisture.. 

Mould is at the cornet in the ceiling. Exterior to it is a garden wall with a gutter running along - we've had the gutters checked and 'although they could do with replacing, it isn't the cause of your condensation/mould' according to the gutter. 

I was thinking the gutter guy would of- course say work would need to be done, but he mentioned it isn't in disrepair.

Also had the pointing of brickwork of the exterior wall checked  - all good

No draught from the window

This is exactly the mould i'm referring too.. Is this damp? — MoneySavingExpert Forum

The 'carpet' is peeling near the skirting and will need to be replaced for sure

Grenage

FreeBear said:

Grenage said:

What's the point in sealing between the floorboards when underlay and carpet are going on top?  That seems like a monumental waste of time

Gripper rods are fixed to the floor leaving a gap of 6-8mm between them and the wall/skirting. The underlay then goes down and is trimmed to fit inside the gripper rods. When the carpet is stretched & laid, the edge is pushed down into the gap between gripper rods & wall/skirting. Whilst this will reduce the draughts coming up from any gap under the skirting, it doesn't hurt to plug the gap and be done with it.

Using expanding foam and a gun, it doesn't take very long to lay down a thin bead - Could probably do a mid sized room in 15-20 mins. Poking a strip of foam (draught excluder ?) with a filling knife might take an hour.

The perimeter sure, but I was just referring to the floorspace.