Attic insulation with no access

Smokey_Bear

I have an attic which has no insulation. There is no access to the space unless I cut a hole in the ceiling slabs.

I had the walls in that part of the house pumped with insulation a couple of years ago but the rooms are still very cold.

I'm wondering what is available to me for insulation?

The space above the slab at the highest point is barely a crawl space.

I have up to 12cm in one room under the ceiling to the closest built-in unit. In another room its less than 6 cm.

The units, floors etc are relatively new and I don't want to touch them. The ceiling needs to be repaired in a couple of places in each room where lights were removed.

Outside, its a concrete tiled roof with a pretty low slope.

Considering the above, what are my options?

Insulate under the slab, insulate the loft or rip off the roof and install insulated panels? (without interfering with the inside of the house)

listermint

Could easily remove some tiles for access and cut the membrane. Then install earthwool across the space up to 300-400mm . Put in new small section of membrane place tiles back on.

The difficulty would be just the space inside.

JimmyMW

https://www.boards.ie/discussion/comment/121405924#Comment_121405924

Similar to this you can get companies to remove a few tiles cut the membrane and blow insulation into the space, repair the membrane and put the tiles back on, no need to actually enter the space. This is often done by these retro insulation companies such as the guys that pump cavities etc, very common in housing estates where the design has a slight jut out for a kitchen or whatever in the rear

Shoog

The problem with this sort of minimally invasive strategy is you have not a clue what you have done to the void ventilation. Chances are you have stopped airflow at the eves which will inevitably lead to condensation and eventual rot.

There are plenty of companies who will do it - but they don't have to deal with the long term consequences.

My view is the only viable solution is to take the whole tiles off and go in from the top or take down all the ceilings and go in from the bottom. Fudge it now and you are looking at replacing the roof within a decade.

listermint

https://www.boards.ie/discussion/comment/121406522#Comment_121406522

Well that's not true at all. My method you're inside rolling the wool out it's non invasive access but gives you control of depth and location.....

Smokey_Bear

So if I was to take a combination of the above advice….

Put a layer of wool in but add vents to either gable to make sure there is some airflow in the loft?

listermint

https://www.boards.ie/discussion/comment/121407324#Comment_121407324

Could swap out some tiles for vent tiles.

Shoog

The issue you may encounter with just adding a few eves vents is it will bypass certain sections of eves and that is where the condensation will build up. Condensation will find the coldest point and that is where the joists/rafters touch the wall plate.

You should be thinking about vents between each rafter and then ensuring that you don't pack your insulation down into the eves blocking the airflow.

On my old house the roof comes right down onto the wall plate leaving no gap at the eve for any ventilation. In the winter on the cold side of the house the rafters get damp at the wall plate. There is no solution short of redoing the roof.