loft conversion floor cold

[neil.carpenter]

hi, our house dosnt seem to hold the heat, heating bills for a detached 3/4 bed house has been circa £300 for gas only.
the house is 1950 traditional brick / cavity build with air bricks.
the gas heating is monitored via a thermostat which we leave in our 1 year old room set at 17 deg.

the house has a loft conversion which has been insulated behind the partition walls. the area i can really feel the cold is on the second level floor.

would insulation in between the joists just at the side of the property stop draft coming up through the cavity and under the floor?

likewise i've considered cavity wall insulation via the polystyrene ball method, however our next door neighbor had problems with the older cavity wall insulation method with damp managing to seep through.

thoughts welcome

 

[robinbanks]

Pull an edge board up and show us a photo

 

[neil.carpenter]

Hi, thanks for your reply. Can you explain what you wanting to see from the photo?

 

[robinbanks]

What's under the cold bit..

 

[neil.carpenter]

Just open space between the trusses. Someone had advised putting the insulation on the internal leaf of the cavity to stop the cold getting under the floor but also allowing air to flow

 

[robinbanks]

If the underside of the floor is draught-open to the world, there isn't any surprise that it's cold. You need to decide exactly what the warm envelope of the house is, and use continuous insulation to delineate it from the world. Having insulation that world air can blow round is pointless

When deciding how to insulate your house, think of it like having a blanket in bed. If you lie on the bed covered in a blanket, and it touches the mattress all round, then you're warm. If you lift one side up, you get cold. If you suspended the blanket from the ceiling 12 inches away from you, then you'd be cold. If you piled the blanket in a ring around you to form a wall, you would be cold. The house needs to "wear a blanket" between the bit you want to be warm, and the world. The parts of the house that will be cold (the roof timbers) need ventilation unless youre sealing the house up so the moisture you generate in your daily life(cooking, washing, breahting) cannot reach the cold surfaces and condense (it needs ventilating out another way; technological solutions exist). If you aren't installing a vapour barrier round the warm envelope, you need to arrange ventilation that flows around the outside of the blanket, not through any part of it

Typically when we talk about "loft conversion" we've changed the loft from a cold draughty place to a warm one by extending the warm envelope/altering the shape of the blanket. If you've left holes in the blanket it's a huge waste of energy

 

[foxhole]

Your floors should be cold , warm would suggest lack of insulation from below.
Thermostat should be in room most often used . Are you heating overnight?