Loft ventilation ,

[rosinante]

I our new hone I have noticed evidence of earlier condensation on the timbers , after fitting a soffit vent it would seem the structure is not suitable for these can,t poke through ,
Google brings up lap vents which open up the overlaps on the felt , the bottom 2 rows are a breathable type and the upper are the pitch fibre type , as an experiment I have shoved a few bits of foam pipe insulation in at easily accessible points daylight can be seen and it feels that air is flowing , the Manthorpe lap vents are £2 plus each and the rough trial of pipe ins seems to be working , the loft is 11m long about 8 m wide and at least 2.5 m high , Q , how many of the vents should I fit ? I can also core drill one gable end for a vent brick or modern equivalent , the other end is not easily accessible, any help , advice , wisdom much appreciated , cheers in advance
Chris

 

[addjunkie]

Pictures makes advice far easier

 

[gaz1]

depends on the style of roof that you have to the ventilation that your needing to have

it would help if we had a photo outside at your roof and also a view of your loft area towards the eaves to the edges of your roof

 

[dobbslc]

I've used tile vents in the mother in laws house and in my place. They seem to work well and are fairly hard to see.

 

[DAPPH]

What membrane do you have under the tiles /slates . why is the void so moist ..leakig roof or some one has pushed the extrator out let into the cavity .
Yes local expert Welsh tradesmen did that to me whilst I was incapacitated _ they also used two incorrect extractors & pipes in the wet rom which condensed the humidity and back filled a U bend in each flexi pipe flooding the motors and burning them out .
The roof membrane was put in 40 years ago oft called the Geoff Capes stuff Kevlar reinforced non breathable mesh between two grey non breathable plastic sheets .
T'would have made a darn good swimming pool liner . Called after Capes because it was advertised with him at 20 stone , being tossed on a sheet of it by several blokes ( Sounds bad whichever way you read it .)
Got a new roof in June last year with a one way breathable membrane and also put a 100 mm piped & louvered vent in at each gable end as well as the correct type & design of extractor fans for the wet room & the kitchen hob area. No more damp even with two long haired gals washing their hair most nights & morning in the shower .

 

[rosinante]

Bottom 2 rows are breathable and upper is the old tar impregnated stuff , I have not long bought the house , concrete tiles , bungalow, no vents at all ,
Chris

 

[gaz1]

I our new hone I have noticed evidence of earlier condensation on the timbers , after fitting a soffit vent it would seem the structure is not suitable for these can,t poke through ,
Google brings up lap vents which open up the overlaps on the felt , the bottom 2 rows are a breathable type and the upper are the pitch fibre type , as an experiment I have shoved a few bits of foam pipe insulation in at easily accessible points daylight can be seen and it feels that air is flowing , the Manthorpe lap vents are £2 plus each and the rough trial of pipe ins seems to be working , the loft is 11m long about 8 m wide and at least 2.5 m high , Q , how many of the vents should I fit ? I can also core drill one gable end for a vent brick or modern equivalent , the other end is not easily accessible, any help , advice , wisdom much appreciated , cheers in advance
Chris

Bottom 2 rows are breathable and upper is the old tar impregnated stuff , I have not long bought the house , concrete tiles , bungalow, no vents at all ,
Chris

i found your older post with the soffit vents reference

pic on post 33

Insulation

Really no easy fix, out properties are just not designed for insulation. Though I'm considering a PIV fan You can get decent thermal plaster boards with foam on the wall side. it's a common way of insulating houses from the inside, but you do make the room smaller on each outside wall by just...

www.mig-welding.co.uk

the pic is correct as long as you have a flow of air from the soffit into the loft area and out the other side thus creating a cold roof method
this area can be blocked off by insulation right up to the tiles which you need an air gap to go through

in other cases
if your soffit area is blocked then the alternative is to fit low roof vents in either side of the roof ridge vents can be used with roof vents as well

 

[DAPPH]

i found your older post with the soffit vents reference

pic on post 33

Insulation

Really no easy fix, out properties are just not designed for insulation. Though I'm considering a PIV fan You can get decent thermal plaster boards with foam on the wall side. it's a common way of insulating houses from the inside, but you do make the room smaller on each outside wall by just...

www.mig-welding.co.uk

the pic is correct as long as you have a flow of air from the soffit into the loft area and out the other side thus creating a cold roof method
this area can be blocked off by insulation right up to the tiles which you need an air gap to go through

in other cases
if your soffit area is blocked then the alternative is to fit low roof vents in either side of the roof ridge vents can be used with roof vents as well

View attachment 459424

That's why I put in the two 100 mm piped through the wall gable end vents with fixed louvers about a metre above the ceilings. So there is always a slow air movement through the roof void above the 200 mm of latest Knauf insulation ,

Most folks don't realise that unless it is foil back ceiling boards, all others usually will allow moisture/ humidity to slowly pass through and up thorough the insulation & then condense in the roof void , It can get worse if you have a wet room that is not vented to the better standards .


Prior to getting the new roof, despite the two incorrect extractors we were suffering loads of black mould in the rooms on the same side of the bungalow .
Now having done nothing but give the mould areas a wipe with a bleaching cloth nothing has reappeared .
The plasticised ceiling emulsions had peeled from the plaster . The coving had come free of the boards and walls in places these were gently pinned back in place .
Now a year later no further moisture problems appear to have happened , my next project after finishing fully boarding the main area between the roof trusses ( too dammed hot at the minute @ 46 oC some days ) is to refit the coving and clean off the flaking emulsion then re roller paint all the ceilings on that side of the bungalow .