condensation in loft shoud I be worried

[addjunkie]

Sofit vents are the norm these days for ventilation

 

[123hotchef]

The trouble is trying to keep the warm air hitting the cold roof. I'm sure some more modern vapor barriers allow condensation to wick through whilst keeping the rain out but felt is not good at doing that. I would keep an eye on it over the next couple of weeks and see if it improves. Might be worth over insulating the ceilings with another 170-200mm if you have the room, time and money, that may stop some of the heat from the rooms below finding its way up there.
The chimney may be not helping although I would imagine most of the heat will have already been absorbed by the brickwork lower down. How warm is the chimney up there have you felt it to see if it's a potential addition to the problem?

i raised the floor in the loft years ago so have 300mm of insulation in there now. i have never fet the chimney breast in the loft although it dose get nice and warm in my bedroom directly below the loft

 

[sparkysy]

Thats good, I think that the most likely source is the boiler and maybe heat from the chimney that have contributed to the issue.
Next time your up there with the fire on see how much heat it radiates.
Also once it warms up a bit that heat should help to dry it out again if you fit some vents so the moisture can escape the loft.

 

[DAPPH]

I looked at a video where these spacers fit inbetween the felt where they overlap and opens up a gap venting the space , looked good

That's the collapsed spring loaded parallelograms of north to south 2 inch wide corrugated plastic ( Think single thickness of house for sale plastic boards ) I said was slipped down the joins of our over lapping roof felt . three row on each roof aspect about every 150mm apart
Most of the condensate is coming up through your ceiling board and possibly the trap door to the roof void . use draught strip to seal it & put sneck hooks & eyes iin the trap door recess to pull the lid down onto the seal Another of ten over look entry of moisture to the roof void is if you have flush mounted ceiling light in upstairs room or the ground floor if you live in a bungalow .added up a dozen light can have the same effect as having a two brick hole in the plaster board and as warm moist air rises tup bhrough the holes it goes .
Despite me removing 18 such flush light fittings in the bungalow including the shower fitted bathroom ( EEK! ) , putting in screwed in backing strips and screwed in hole saw cut filler blanks then getting a plasterer to plaster all our ceilings over the gopping Artex .

We still had condensation and a light mould forming on the roof trusses as well as very wet carboard boxes stored in the roof void . I eventually traced it to a four yer old professionally fitted kitchen where the " hero's" had pushed the outlet into a cored drilled cavity a couple of inches and simply stuck a louvered vent over the core drilled outer wall That as well as cutting up one side of the dryer hose so they could fit it over the five inch outlet of the extractor, then using masking tape wrapped it to make some sort of iffy seal to the pipe and flange , hidden behind the false stainless steel chimney was also a nine inch hole for the four inch pipe .

It can't have been long before the masking tape gave up the ghost and the cut in the tube started to vent back into the kitchen as well as it all eventually escaping into the roof void via the open 9 inch hole ,
Most of the moisture extracted was simply vented inside the cavity . Eventually sorted with the help of four inch dia flexi aluminium pipe from Wickes and a carefully cut to requirement UV resistant black 6 inch 1 litre plant pot and a cartridge of " Sticks Like " building adhesive .


As a result of all this hassle , it led me purchasing a £12 or so temperature and humidity device which is fitted to the hall way wall , now humidity is usually 42 to 45 % and occasionally 56 % till I close all doors ,windows & trickle vents and get the dehumidifier going as dry air costs less to heat than moist air by a considerable amount .

I've also core drilled a slightly angled down four inch clearance hole through both gable end walls about three feet up in the roof void then sleeved them with new cut to size 105 mm clean sealed in waste pipe.
As I wanted ( and got ) dry- ish air gently moving through the roof void to make my own cured hams & salami etc in the winter months whilst its reasonably cool and to store a few containers of maturing home made black & elderberry home made wine .
When I last looked about this time last year we no longer had any condensation on the grey plastic sheeting used as a felt substitute 44 years ago when the bungalow was built .

 

[DAPPH]

i do not see any vents up in the loft, none in the roof, eves or soffits

Poor chimney pointing up & flashings plus bad workmanship can also let in tremendous amounts of water, it's not often a roof repair or new work is looked at for reliability once it's been paid for .

 

[123hotchef]

I might open the lot hatch and leave the dehmidifier on for the day, it runs most days for a while anyway but with the hatch open it will help dry it out

 

[123hotchef]

I suppose it was never meant to be rammed full of stuff....
I am going to order 20 of those vents and fit them on the 3 sides for some ventilation.

 

[MattF]

noticed a few wet boxes today

I could but hope to notice something like that.

 

[voipio]

Considering the low temperatures we've been having the last few days, that roof space doesn't look too bad. Bear in mind, if there's frost on the outside of the roof tiles/slates/whatever, chances are something similar will be going on on the inside surface, albeit under the influence of the slightly higher temperature arising from the heat losses from the house.

 

[123hotchef]

It's all dry up there now the hatch has been left open and the dehumidifier left on,on the landing for a few hours

 

[Brad93]

your 300mm of insulation. did you put a vapour control barrier above it?

 

[123hotchef]

No that should be below it. IMO.

 

[gaz1]

you need to insulate and seal the loft area as that boiler and the heat up there is causing you the damp situation

theres no point in fitting air breathers as that boiler will end up flat cold and freezing in this case beter to go the opposite way and insulate the rafter beams and seal them with overlaped insulation boards

pick your punishment on the insulation rockwoll vs eps and both need eps 1" overlaped eps board to seal the rafters away from, the beams

 

[123hotchef]

you need to insulate and seal the loft area as that boiler and the heat up there is causing you the damp situation

theres no point in fitting air breathers as that boiler will end up flat cold and freezing in this case beter to go the opposite way and insulate the rafter beams and seal them with overlaped insulation boards

pick your punishment on the insulation rockwoll vs eps and both need eps 1" overlaped eps board to seal the rafters away from, the beams

are you saying insuate inbetween the rafters or over the top

 

[gaz1]

insulate between the rafters 2" 3" 4" up to you on what type you use

then do another coat over the beams with 1" eps insulation

at moment your boiler is within the loft that is not really sealed up to a degree

you open that up with vents and you will make it cold/ freezing cold that boiler will kick on and fire up to stop itself from freezing

something like this
the insulation below the rafters can be either 2" or 1" you choose
if you dont want to do it all the way down then dont just put woods in like below and just insulate inbetween the woods and over them

 

[123hotchef]

food for thought that, I will keep a check on it up there, it dried out pretty quick with the hatch open yesterday and the dehmidifier on for 5 hours

 

[gaz1]

depending on your rafter thickness say they are 5" rafters then 4" loft insulation will do with a 1" eps board over it is plenty enough

also leaves a gap at the slate side to run up and over the house

string netting can hold it up whilst you over board it but dont forget add a second board or a latte for the join of the 8x4 sheets or the 8x2 sheets and tape them up

but i bet your boiler has been firing up alot whilst in that freezing weather weve just had just to stop itself from freezing up within the boiler and those upstairs pipes in the loft as it would have been cold up there

 

[Keithmac]

We get condensation on the sarking felt, roof has been up since 1950's and still in good condition so I don't worry about it personally.

Loft space is freezing cold at moment (which is a good thing as I'm not paying to heat dead space!).

 

[Morrisman]

I would wait until the temperature normalises and check again before doing anything. We don't often get a prolonged cold spell like this.

Everything is chilled to the bone, then we get a sudden warm moist front pass through, hot moist air hits cold items = condensation.
My garage did it yesterday, I opened the front and back doors to sort things out after the boiler leak and suddenly everything was dripping wet, every hard or shiny surface glistening with condensation, just like the plot in the rusty garage thread. Two hours later it is all dry again.

 

[The Artilleryman]

I've had a drip line along the length of our loft - have been in and out of the loft recently - 1st time it's been this cold since we moved in 4 years ago.

Trap door will be the culprit for warm air as it hinges down.

Standard 100mm of insulation, will add another 200mm, but if my calculations are correct, this will add 500kg to the weight of the roof - 288M2 /5.5M2 x 10.35kg (area / pack area x pack weight). And yes it's a large bungalow.

Frustratingly ASCI codes don't work.