Loft Ventilation Conundrum

[fresia]

We have a chalet style 1950s Scottish house with the second floor rooms con= tained within the roof space (not a loft conversion). There is a loft space= above the rooms but also small loft spaces in the eaves on either side of = the upstairs rooms accessed through small doors in the bedroom walls.

We want to insulate these spaces but are not sure what type of ventillation= to install in them to prevent damp. The roof is constructed of wooden boar= ds overlaid by felt then tiles. Each eaves space is only on one side of the= house and not connected with loft space above to allow circulation of air.= If we install tile vents, we presume there will not be the means for the a= ir to circulate in these areas?

A further factor is that the soffits are made of concrete and therefore it = is not possible to vent through these.

Any suggestions?

[george - dicegeorge]

contained within the roof space (not a loft conversion). There is a loft space above the rooms but also small loft spaces in the eaves on either side of the upstairs rooms accessed through small doors in the bedroom walls.

install in them to prevent damp. The roof is constructed of wooden boards overlaid by felt then tiles. Each eaves space is only on one side of the house and not connected with loft space above to allow circulation of air. If we install tile vents, we presume there will not be the means for the air to circulate in these areas?

not possible to vent through these.

My loft spaces are cold in winter because the insulation layer is below them. It's up to you where the insulation envelope is, but you do need ventilation in that roof.

Ibought this book, its cheaper than a sheet of kingspan, and canadian where they have great temperature differences inside and outdoors.

[Bill Wright]

contained within the roof space (not a loft conversion). There is a loft space above the rooms but also small loft spaces in the eaves on either side of the upstairs rooms accessed through small doors in the bedroom walls.

install in them to prevent damp. The roof is constructed of wooden boards overlaid by felt then tiles. Each eaves space is only on one side of the house and not connected with loft space above to allow circulation of air. Now are you sure? I work as an aerial installer and I find that houses of that type always have an easy means of getting cables from the small side lofts to the main one. Usually the link is between the underside of the roof boards and the sloping plasterboard of the bedrooms. Normally this gap is packed with insulating material. Sometimes there are pieces of plasterboard (etc) filling the gaps between the joists, but these can simply be removed. If there is a tank in the top loft some of the pipes might go down to the small lofts and that will show you the route. I normally make a cable route through by pushing a length of drainrod through the gap.

Bill

[harry]

ontained within the roof space (not a loft conversion). There is a loft spa= ce above the rooms but also small loft spaces in the eaves on either side o= f the upstairs rooms accessed through small doors in the bedroom walls.

on to install in them to prevent damp. The roof is constructed of wooden bo= ards overlaid by felt then tiles. Each eaves space is only on one side of t= he house and not connected with loft space above to allow circulation of ai= r. If we install tile vents, we presume there will not be the means for the= air to circulate in these areas?

t is not possible to vent through these.

The normal solution is to insulate the ceilings and to put in air bricks in the gables or tile ventilators in the roof to ventilate the spaces.

Your problem is gonna be insulating the sloping bits of ceiling (if there are any).

The boards you mention are called sarking boards. A Scottish tradition.

[Tim Watts]

You can either insulate the ceilings and add some vents into the loft space as others have suggested, or insulate between and under the rafters.

If going between rafters, you can either use wool (glass/sheeps) or celotex type boards.

Usually, with non breathable sarking you would need 50mm of air space between the top of the insulation and the underside of the roof covering - and this space would need to be ventilated top and bottom on every rafter run.

Your local Building Control inspector (or whatever they are called in Scotland) should be able to advise - I would invite him round for tean and biscuits - IME they ar eoften very helpful.

HTH

Tim