suspended floor,room freezing.

bassy

hi all I live in a very old house must be 80 yrs old,mass concrete.
bedroom is freezing,new pvc double glazed window,the attice was fully insulated 3 yrs ago and theres one radiator in the room its a single rad measuring 44 x 20 inches,will replace that with a new twin radiator.
the room size is as follows 9ft wide 8ft long 9ft3 high.

the cold I think im sure is coming from the floor as its a suspended floor and one corner seems rotten and gaps in it from the wall,years ago I laminated flooring over the original floor boards.

but now I feel its time for the lot to be lifted,when I totally strip the original old floor and im left with the joyces,what should I do to insulate?
membrane under the joyces and then some rolls of fibre glass between the joyces ?.

any ideas would be truly great or anyone on here who has had a similar problem and job to mine.

MicktheMan

bassy wrote: »

hi all I live in a very old house must be 80 yrs old,mass concrete.
bedroom is freezing,new pvc double glazed window,the attice was fully insulated 3 yrs ago and theres one radiator in the room its a single rad measuring 44 x 20 inches,will replace that with a new twin radiator.
the room size is as follows 9ft wide 8ft long 9ft3 high.

the cold I think im sure is coming from the floor as its a suspended floor and one corner seems rotten and gaps in it from the wall,years ago I laminated flooring over the original floor boards.

but now I feel its time for the lot to be lifted,when I totally strip the original old floor and im left with the joyces,what should I do to insulate?
membrane under the joyces and then some rolls of fibre glass between the joyces ?.

any ideas would be truly great or anyone on here who has had a similar problem and job to mine.

If by "membrane" you mean vapour barrier then don't do that, whatever you do. Vapour / airtight barrier always on the warm side.

bassy

MicktheMan wrote: »

If by "membrane" you mean vapour barrier then don't do that, whatever you do. Vapour / airtight barrier always on the warm side.

its like a breather type stuff that is used under slates on roofs etc

https://www.amazon.co.uk/HIPERNOVA-Underlay-Polypropylene-Temperature-resistance/dp/B00NEH0IM6

bassy

MicktheMan wrote: »

If by "membrane" you mean vapour barrier then don't do that, whatever you do. Vapour / airtight barrier always on the warm side.

can you explain some more please as I don,t quite understand.

MicktheMan

Installing a vapour barrier on the cold side of insulation will result in the real risk of condensation forming and wood rot (floor joists) over time.

bassy

MicktheMan wrote: »

Installing a vapour barrier on the cold side of insulation will result in the real risk of condensation forming and wood rot (floor joists) over time.

so install the membrane with the warm side facing up looking at me and put rolls of fibre glass over it between the joyces ye?

or what would you recommend if it were you ?.

MicktheMan

Fibre insulation supported by netting stapled to joists, then airtight membrane lapped and taped and also sealed / taped to all walls, then floor boards.

listermint

MicktheMan wrote: »

Fibre insulation supported by netting stapled to joists, then airtight membrane lapped and taped and also sealed / taped to all walls, then floor boards.

This.

And frankly I don't think laminate floor creates a warm room never has. Put down carpet it's always cosier.

And as Above pay very special attention to the airtight membrane and the tape seals at the walls.

bassy

listermint wrote: »

This.

And frankly I don't think laminate floor creates a warm room never has. Put down carpet it's always cosier.

And as Above pay very special attention to the airtight membrane and the tape seals at the walls.

air tight membrane is that polythene ?.

listermint

bassy wrote: »

air tight membrane is that polythene ?.

It's not. But polythene of a certain guage could be used.

Airtight membranes tend to have a fibre structure in them for strength and rigidity. Much easier to work with. But will have the price to match it.

bassy

listermint wrote: »

It's not. But polythene of a certain guage could be used.

Airtight membranes tend to have a fibre structure in them for strength and rigidity. Much easier to work with. But will have the price to match it.

would this be suitable ?

https://www.amazon.co.uk/HIPERNOVA-U.../dp/B00NEH0IM6

listermint

bassy wrote: »

would this be suitable ?

https://www.amazon.co.uk/HIPERNOVA-U.../dp/B00NEH0IM6

For beneath the joists to hold up the insulation yes it must be breathable. Screwfix do a roll for 35 euro.

For airtightness no it's not the right stuff. Top of the joists need airtight membrane

kevcos

Likely that some of the joisting is rotten?

Perhaps then consider ripping everything out and filling the entire void space with rigid insulation and pouring a screed on top.

Obviously economics of this depends on the depth of the void space under the existing joists.

bassy

kevcos wrote: »

Likely that some of the joisting is rotten?

Perhaps then consider ripping everything out and filling the entire void space with rigid insulation and pouring a screed on top.

Obviously economics of this depends on the depth of the void space under the existing joists.

im afraid that's not a option.

kevcos

bassy wrote: »

im afraid that's not a option.

Why not? Too costly?

bassy

kevcos wrote: »

Why not? Too costly?

yes to pricey im afraid.

loyatemu

there's quite a bit of information online about insulating suspended timber floor, and some products specifically designed for it:

https://www.ecologicalbuildingsystems.com/Ireland/Blog/Post-Detail/A-Best-Practice-Approach-to-Insulating-Suspended-Timber-Floors

kevcos

loyatemu wrote: »

there's quite a bit of information online about insulating suspended timber floor, and some products specifically designed for it:

https://www.ecologicalbuildingsystems.com/Ireland/Blog/Post-Detail/A-Best-Practice-Approach-to-Insulating-Suspended-Timber-Floors

Very good article!

listermint

loyatemu wrote: »

there's quite a bit of information online about insulating suspended timber floor, and some products specifically designed for it:

https://www.ecologicalbuildingsystems.com/Ireland/Blog/Post-Detail/A-Best-Practice-Approach-to-Insulating-Suspended-Timber-Floors

Always be wary of the pricing on some of the eco passive stuff . Some of its astronomical and you can get similar same products without the specific branding.

Tapes and membranes can be obtained at all budgets believe me I've bought them all. And the cheaper stuff is just as good especially indoors.

Yellow_Fern

Did you ensure that any vents under the floor, visible from the outside are open and working?

bassy

Yellow_Fern wrote: »

Did you ensure that any vents under the floor, visible from the outside are open and working?

theres one vent and yes open and its fine.but the cold is coming in from there also as some of original floor boards are rotten in the corner from a long standing tiny leak in rad that I discovered the other day.

my house is pre 1950,s and it completely mass concrete,and I spoke to a builder yesterday and he told me im at nothing with the floor cause the room and other rooms will still be cold because he said all the window walls in the house need to be dry lined because the mass concrete walls is taking any heat that's producded in the room.

he said im entitled to it all under the heat scheme grants because the house is so old.

listermint

Heat scheme grant is based on age of owner though not age of house.

There are other grants available for refurbishment again anyone can apply on any age house

bassy

listermint wrote: »

Heat scheme grant is based on age of owner though not age of house.

There are other grants available for refurbishment again anyone can apply on any age house

my mum is a pensioner.

bassy

listermint wrote: »

Heat scheme grant is based on age of owner though not age of house.

There are other grants available for refurbishment again anyone can apply on any age house

think you are wrong on that,cause the builder I was talking to yesterday carrys out all that work for the heat schemes etc and he told me it woul,nt matter if it was millionaires living in that house as long as the house is over 60 yrs old and mass concrete then that house qualifies for it,he said doesn't matter who lives in the house.

listermint

bassy wrote: »

my mum is a pensioner.

Well was just clarifying the comment. It might cause others to think its true.

Yellow_Fern

bassy wrote: »

theres one vent and yes open and its fine.but the cold is coming in from there also as some of original floor boards are rotten in the corner from a long standing tiny leak in rad that I discovered the other day.

my house is pre 1950,s and it completely mass concrete,and I spoke to a builder yesterday and he told me im at nothing with the floor cause the room and other rooms will still be cold because he said all the window walls in the house need to be dry lined because the mass concrete walls is taking any heat that's producded in the room.

he said im entitled to it all under the heat scheme grants because the house is so old.

The vent does let in cold but you can work around that to minamise impact. Just dont close it.

What he said is misleading. Its true that the walls will be cold. They will be a weak spot until you insulate, ideally from external side not the internal side although both are possible. It is not true that any other effort will be a waste of time. It is possible that draughts from the floor might be more significant. If you are a budget you and have patience you could find some one to replace the rotten parts, install insulation and membrane. This would be a very good solution is done with care and precision. If this is too expensive you could just mix sawdust and wood glue and use it fill the gaps between the floor boards. Make sure this is done in winter so you can feel the cold air to guide you.