Attic Insulation Advice

superd1978

Hi Guys,

I have a 3 storey house, 3rd floor more an attic converted, which is currently a spare bedroom.

My problem is during winter this room is absolutely freezing.

The layout is split about 60/40. 60 being the living space, the other 40 being unconverted attic space. Its an apex type roof.

There is a door which leads from living area to attic space, which could probably do with better insulation.

I have also noticed some felt is completely gone, and lots of air blowing straight in. This i intend to fix.

My main question, all of the unconverted attic space is insulated except the actual (apex) roof itself. Can i insulate over the felt of an apex roof without causing any condensation issues or similar? Or even some of the area?

A friend mentioned i should not do this, as it might lead to rotting wood over time, that some air space is needed in the attic.

I believe fixing the felt issue and insulating most of the apex roof will drastically improve the cold air coming in through roof tiles / felt.

Has anyone any thoughts they can share here?

Thanks in advance.

BrokenArrows

im having a hard time visualizing what is insulated and not.
Can you draw a quick picture.

superd1978

Thanks for reply mate...

Can you access this image?

https://photos.app.goo.gl/WbFQfpTwDaVfb2nM6

Note, water tanks and pipes are in the unconverted attic space. Not sure if that has a bearing on things.

listermint

Replace the felt, Insulate the entire non living space section. And you may have to look at pulling the plasterboard down from the living space section. Because you wont find a method to insulate the roof space in the living section with no access. Opposite way would be to remove roof tiles and the felt and insulate from outside.

Either way it sounds like the builder who did the work did a crap job of it. Air flow and minimal insulation is the key problems with rooms like that.

BrokenArrows

superd1978 wrote: »

Thanks for reply mate...

Can you access this image?

https://photos.app.goo.gl/WbFQfpTwDaVfb2nM6

Note, water tanks and pipes are in the unconverted attic space. Not sure if that has a bearing on things.

If the red section is insulated properly there should be no need to insulate the black area in the unconverted space.

When you go into that room in the winter how does the wall to the unconverted space feel? Is it excessively cold to the touch?

Id say your problem is that the warm air is escaping through the door and the cold draft is coming into the room.

1. Fix the felt causing the air to blow in should be your first priority.
2. Sort out the door and that wall to make sure the door closes with a well insulated seal. There should be no flow of air though that door.
You should have 300mm of rockwool insulation on that wall at least.
3. If the room is still cold then the heat is escaping from other areas in that room too.

superd1978

Much appreciate guys.

First job is fix the felt.

Second job i think im going to insulated as much as i can of the uninsulated space.

Third i will try better insulate the door. I did buy that rubber sealant tape for where doors meest the frame, but its a bit shabby i think.

Thanks again.

Calahonda52

Before you dive in there, can we have a picture of the insulation in the red marked slope bit just as it turns to black.
A similar picture of the bottom corner between attic ceiling and knee wall.
Is that ceiling floored?

superd1978

Calahonda52 wrote: »

Before you dive in there, can we have a picture of the insulation in the red marked slope bit just as it turns to black.
A similar picture of the bottom corner between attic ceiling and knee wall.
Is that ceiling floored?

The "Living Area" is completely plastered, no access to see anything.

Calahonda52

superd1978 wrote: »

The "Living Area" is completely plastered, no access to see anything.

from inside: see the red and blue boxes on attached

GreeBo

Where is the "felt" you are talking about fixing?
Felt should be irrelevant if the living space is insulated?

You cant just lash insulation into a defined cold space, you will have issues with damp and mould if you remove ventilation from the cold area that contains your water tank etc.

Is there insulation *under* the living space? If there is this is stopping any heat from the rest of the house getting to this room. (you have insulated it like a fridge, keeping heat out)

Also whats the heat source for this space?

Lumen

You need to decide whether you want a warm attic or cold attic, i.e. where do you want the boundary of your heated, conditioned space, then insulate that boundary with an air barrier on the warm side to prevent humid air condensing in the insulation.

IMO the decision should be based on where you have the best access to do the work.

If you go for cold attic you must ensure that cold air cannot penetrate under the floor of your converted space.

Insulation is not generally an air barrier.

MicktheMan

This^^^^^^^^^^

superd1978

Calahonda52 wrote: »

from inside: see the red and blue boxes on attached

I took some pictures of this, just having trouble uploading from work.

Basically from the red to blue its completely insulated from top to bottom, and the insulation seems to run under the ceiling of the living area.

Thanks for taking the time here.

superd1978

Lumen wrote: »

You need to decide whether you want a warm attic or cold attic, i.e. where do you want the boundary of your heated, conditioned space, then insulate that boundary with an air barrier on the warm side to prevent humid air condensing in the insulation.

IMO the decision should be based on where you have the best access to do the work.

If you go for cold attic you must ensure that cold air cannot penetrate under the floor of your converted space.

Insulation is not generally an air barrier.

Thank you very much for the advice....

superd1978

GreeBo wrote: »

Where is the "felt" you are talking about fixing?
Felt should be irrelevant if the living space is insulated?

You cant just lash insulation into a defined cold space, you will have issues with damp and mould if you remove ventilation from the cold area that contains your water tank etc.

Is there insulation *under* the living space? If there is this is stopping any heat from the rest of the house getting to this room. (you have insulated it like a fridge, keeping heat out)

Also whats the heat source for this space?

Thanks for the insight greebo.

Ill be honest, I havnt got much of a clue around insulation. Im just trying to come up with ways to reduce how cold the living space will be over coming months.

I think the root of the cold is probably the door. If thats well insulated, it doesnt really matter whats going on in the attic.

Ill tackle that first and see where im at then.

Thanks for all the advice. You guys are amazing.

Calahonda52

superd1978 wrote: »

Thanks for the insight greebo.

Ill be honest, I havnt got much of a clue around insulation. Im just trying to come up with ways to reduce how cold the living space will be over coming months.

I think the root of the cold is probably the door. If thats well insulated, it doesnt really matter whats going on in the attic.

Ill tackle that first and see where im at then.

Thanks for all the advice. You guys are amazing.

What goes on in the attic is key because if cold air passes through the glass fibre insulation on ceiling or along the slope or the vertical knee wall the insulation is worthless.
this is why I asked to see the pictures we discussed.:)

https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

superd1978

Calahonda52 wrote: »

What goes on in the attic is key because if cold air passes through the glass fibre insulation on ceiling or along the slope or the vertical knee wall the insulation is worthless.
this is why I asked to see the pictures we discussed.:)

https://www.nsai.ie/about/news/publication-of-sr-542014-code-of-practice

Thanks again mate

uck51js9zml2yt

I was looking at this last night with the same idea for my attic space.
Am I right in thinking this is how it works from the outside -in
Roof Tiles, (gap), insulation, membrane, plasterboard, attic space?

listermint

Allyson Cuddly Table wrote: »

I was looking at this last night with the same idea for my attic space.
Am I right in thinking this is how it works from the outside -in
Roof Tiles, (gap), insulation, membrane, plasterboard, attic space?

Roof tile. Roof felt. Gap. Insulation card. Insulation. Air tight membrane plasterboard . Attic.

Ush1

Your problems sound more related to air tightness than insulation.