Sorry if this is a stupid question, but I am trying to get to grips with this DIY stuff.
I read that standard loft joist spacing is 60 cm or 40 cm. I also read that the vapour barrier is supposed to be continuous. Does that mean that the vapour barrier should continue under the joists?
In my house, there seems to be a 2 cm gap between the underside of the joist and the ceiling plaster board. I think the ceiling is spaced from the joists by some metallic strips that the ceiling bopards are mounted on.
Now, if the vapour barrier is supposed to be continuous, I guess you are supposed to space the joists at 60 cm between centres. Say you are using 4 cm wide joists, then you would move 2 cm of wool aside on each side of the insulation strip so that the paper can meet in the middle under the joist.
But .... my joists are at intervals of 63.5 cm. Which I guess is no conincidence because my roof trusses are 3.5 cm wide. That leaves an exact gap of 60 cm between each joist for the insulation, not 60 cm between centres. But is also means that the vapour barrier is discontinuous, by the width of the joist. Is this normal practice?
I read that standard loft joist spacing is 60 cm or 40 cm. I also read that the vapour barrier is supposed to be continuous. Does that mean that the vapour barrier should continue under the joists?
In my house, there seems to be a 2 cm gap between the underside of the joist and the ceiling plaster board. I think the ceiling is spaced from the joists by some metallic strips that the ceiling bopards are mounted on.
Now, if the vapour barrier is supposed to be continuous, I guess you are supposed to space the joists at 60 cm between centres. Say you are using 4 cm wide joists, then you would move 2 cm of wool aside on each side of the insulation strip so that the paper can meet in the middle under the joist.
But .... my joists are at intervals of 63.5 cm. Which I guess is no conincidence because my roof trusses are 3.5 cm wide. That leaves an exact gap of 60 cm between each joist for the insulation, not 60 cm between centres. But is also means that the vapour barrier is discontinuous, by the width of the joist. Is this normal practice?