loft insulation and ventilation ??

longforgotten

Do you have to have some sort of ventilation in your roof space, especially if you have loft insulation ? I'm thinking particularly of an old house.

I'm just wondering if without ventilation loft insulation may result in problems. Don't know why I've got this in my head, .....must have heard about it from somewhere but am I mixing it up with something else ??...

Any advice welcome

Mutton_Geoff

There should be ventilation along the eaves. Get up there and see if you can see daylight coming in. If you lay extra insulation, just don't roll it up against the inside of the roof tiles, leave a small gap so you can still see the gaps.

27col

I believe that modern housing does have ventilation in the roof. My 1977 self build does not, but we have never had any condensation problems. I expect that there is leakage of air at the eaves. Just so long as it is above the insulation and not below it then no problem.

moonrakerz

The rules and regs about loft ventilation seem to cause more problems than the ones they are supposed to cure.
I moved into a new house in 1986 with yards of loft insulation and ventilation all round. The first winter I was there my pipes froze up ! because, in effect the temperature in the loft was the same as outside.
Good job for global warming, we don't get really cold winters anymore.

You can't win !

27col

I believe it is normal to leave a small area under the roof tank clear of insulation to prevent freeze ups. That said, both the tank, and any associated pipe work should still be well lagged. As moonrakerz says, we almost never get cold winters in this neck of the woods. (Hampshire)

rebon

You must have ventilation in the roof space or you run a risk of condensation and dry rott. Make sure you have plenty ventilation.

Look here for advise...
http://www.harcon.co.uk/build.aspx

moonrakerz

rebon wrote: »

You must have ventilation in the roof space or you run a risk of condensation and dry rott. Make sure you have plenty ventilation.

Look here for advise...
http://www.harcon.co.uk/build.aspx

That is the line given, but with modern pressure treated timber I wonder just how true this really is !

Mutton_Geoff

I moved into a new house in 1986 with yards of loft insulation and ventilation all round. The first winter I was there my pipes froze up ! because, in effect the temperature in the loft was the same as outside

That's a good advert for the insulation standards isn't it? You wasted no money heating the loft space! If the pipes were properly lagged, they wouldn't freeze, but there is no need to waste money all year round heating the loft to prevent this when £10 worth of foam lagging would have helped?

moonrakerz

Mutton_Geoff wrote: »

If the pipes were properly lagged, they wouldn't freeze, but there is no need to waste money all year round heating the loft to prevent this when £10 worth of foam lagging would have helped?

The pipes were lagged ! Lagging doesn't create heat - it just helps to preserve what heat there may be there in the first place, if the loft is well below zero the pipes will freeze almost as quickly as if there was no lagging.
Perhaps I did save on few bob on my oil bill but I had a loft full of water and had to made holes in the bedroom ceilings to let the water out. Very money saving !