steps to identify and fix Damp\Condensation and a cold room

[Zelfer]

Hi.

As the weather has got colder, we've started to suffer some significant condensation issues on the walls of our 1960s cavity walled house that we have moved into this year which appear significantly colder than I would ever expect them to be given that they do have insulation (beads) installed. The roof typically has 10cm of insulation in my opinion reasonable condition, with a chipboard flooring installed on top. The house has double glazing, generally in good condition (the frame seal is slightly peeling, waiting for a dry day to remove and replace it) We didn't get a house buyers survey due to a screw up at the application stage, and felt that so many of them appear to juat cover their arses with 'get an additional, independent survey for this' it seemed reasonable to put the £400 as side to cover any surveys we found we needed.

The house ( a bungalow) is built on a clay soil at the top of a hill, has a suspended wooden floor, and appears to have no underfloor insulation. I haven't yet looked under the floorboards, due to wife wanting new easy cleaning laminate flooring (think of the cleaning needed with toddler and crawling baby with the muddy dog to clean up after) instead of an emergency fix budget, so can't currently easily get under it.

I'm trying to work out the best place to start, and a to do list. I'm looking at green deal for underfloor insulation, but not sure how much that may assist in addressing the cold walls.

The house also has a large soffit/eave, with a 30cm soffit all the way around with a vent pre cut into it the full way around.

Given the time of year and the wife's inability to stop spending money we don't have, I'm trying to plan and budget the most efficient steps as this will be credit carded.

So I'm thinking:-
1) Spend £150 on a dehumidifier to reduce impact of problem.
2) get 2 local builders in (free but biased survey effectively) to see of the guttering/facias are faulty, causing penetrating damp.
3) get an energy assessment done ( and ensure this covers a thermal image of the problem walls to check cavity wall insulation is OK/ cavity is not crossed) (£175)
4) get professional to reseal all windows (£300)
5) try and get underfloor insulation on green deal (£0)

Would you recommend anything else?

(This is on top of a mice problem that has developed over Xmas week )


Thanks in advance!

W

 

[foxhole]

VENTILATION is free and the only way to remedy condensation, with adequate ventilation you won't get any significant condensation.
Impossible to heat a property to the point the walls are warm enough to prevent condensation.
More heat also means the air can support more moisture.

 

[Zelfer]

VENTILATION is free and the only way to remedy condensation, with adequate ventilation you won't get any significant condensation.
Impossible to heat a property to the point the walls are warm enough to prevent condensation.
More heat also means the air can support more moisture.

Yep, ventilation does need to be taken into account, but for a 3 bed bungalow with only 2 people in it, that's currently drafty and freezing despite the heating being on, the amount of ventilation in place gives me what should be more than enough ventilation.


I'm really surprised that with outside being -1, the inside of a cavity wall isn't warmer than 6 degree (meausred with a digital thermometer held against the wall.., surely that's an indication of a serious breeze /damp problem?

 

[foxhole]

You have mechanical ventilation in kitchen and bathroom? permanently open vent to kitchen and bathroom plus vents to most rooms? Minimum requirements for a well ventilated property.
In addition no washing should be dried indoors?

Household Activity Average moisture added to the indoor air

Cooking 3.0 litres day

Clothes washing 500 ml per day
Showers and baths 1.5 litres per day per person
Dishes 1.0 litre per day
Clothes drying (unvented) 5.0 litres per load
Gas heater (unflued) 1.0 litre per hour
Breathing 20ml per hour per person
Pot plants As much as you give them

 

[JohnD]

does anybody drape wet washing around your home?

Are the windows misty?

Where do the draughts come from?

How thick is the loft insulation?

Looking at the meter readings, how much gas have you used since the last reading? What are the two dates?

 

[Zelfer]

You have mechanical ventilation in kitchen and bathroom? permanently open vent to kitchen and bathroom plus vents to most rooms? Minimum requirements for a well ventilated property.
In addition no washing should be dried indoors?

Household Activity Average moisture added to the indoor air

Cooking 3.0 litres day

Clothes washing 500 ml per day
Showers and baths 1.5 litres per day per person
Dishes 1.0 litre per day
Clothes drying (unvented) 5.0 litres per load
Gas heater (unflued) 1.0 litre per hour
Breathing 20ml per hour per person
Pot plants As much as you give them

Thanks for the details, I was working with this info as a basis previously compared to my usage and the knowledge that I have mechanical extraction in the bathroom and kitchen.
We don't dry clothes indoors on rads, it's done in a tumble dryer or in the garden, and dishes are done via a dishwasher.

The very local guy who lives in an identical house the next row across and has done for 15 years, had the same problem the first year they had cavity wall insulation fitted and he walked me through his problem. This was confirmed to apply to my house by getting into thr roof space and watching the condensation on the bottom of the bitumin fabric where that's running down the rafters with the top 1cm of most rafters being wet and transferring to top of the bricks, then dropping behind the coving and down the internal wall, caused by what appears to be a recent loft insulation and cavity wall top up blocking a load of the eaves on one side, and despite the soffits all being vented, his experience shows that it's not enough for a south facing gable end even if the eaves are cleared.

The cold wall appears to be caused by being wet bricks, which are then acting as condensing points for further internal humidity.

First plan is to clear the eaves, then fit 6 tile vents, and review the need for a positive pressure system, or a humistat driven vent.

In the meantime, I'm sticking a humidity and temp sensor each room that takes measurements each ten minutes that a friend lent me today.

Now I know what I'm looking for, I can see that almost all the neighbours have tile vents fitted.

The other 2 guys took a bunch of damp meausrements which all showed as dry, then tried to sell me positive pressure ventilation which would extract air from the loft, and didn't even look in the loft...

Thanks for the help.

 

[Zelfer]

does anybody drape wet washing around your home?

Are the windows misty?

Where do the draughts come from?

How thick is the loft insulation?

Looking at the meter readings, how much gas have you used since the last reading? What are the two dates?

Windows aren't misty.
Draughts appear to come from the windows themselves, and we can currently hear road noise and bird song despite the windows being closed and pulling the handles doesn't improve matters, and that's after a tweak of the mushrooms - so seal or sealant has perishsed.

Loft insulation is 10cm + boardings

Gas : 155 units between 11th Nov and 11th dec on a non condensing boiler.

 

[JohnD]

does anybody drape wet washing around your home?

 

[Zelfer]

does anybody drape wet washing around your home?

Sorry. Missed that one.
No, tumble drier or clothes line.

 

[JohnD]

if it is truly draughty (not just cold air streaming down window glass due to heat conduction) then it should have reasonable ventilation. I wonder where the excessive moisture is coming from.

Have you checked for spilling gutters or leaking downpipes?

Do you have a water meter?

Have a look in the loft, for leaks generally, and at the feed and expansion tank for the boiler. Is the ballcock constantly dripping to refill? If you tie the float up for a week, does the water level drop?

If your loft has gable walls you can core-drill vents or put in airbricks, that will give a good flow of air.

You might have a rusty radiator, or an unseen leak under the floor. Pull up a board and have a sniff for damp. Also look under the sink and bath. A powerful extractor, preferably an inline ducted fan in the loft, will make a big difference.

The water supply pipe under the floor may be leaking. A young person with sharp ears may notice the difference, especially at night, if you turn the outside stopcock on and off.

Your gas usage is rather low, especially for an old boiler, and would not keep my house warm.

 

[Zelfer]

if it is truly draughty (not just cold air streaming down window glass due to heat conduction) then it should have reasonable ventilation. I wonder where the excessive moisture is coming from.

Have you checked for spilling gutters or leaking downpipes?

Do you have a water meter?

Have a look in the loft, for leaks generally, and at the feed and expansion tank for the boiler. Is the ballcock constantly dripping to refill? If you tie the float up for a week, does the water level drop?

If your loft has gable walls you can core-drill vents or put in airbricks, that will give a good flow of air.

You might have a rusty radiator, or an unseen leak under the floor. Pull up a board and have a sniff for damp. Also look under the sink and bath. A powerful extractor, preferably an inline ducted fan in the loft, will make a big difference.

The water supply pipe under the floor may be leaking. A young person with sharp ears may notice the difference, especially at night, if you turn the outside stopcock on and off.

Your gas usage is rather low, especially for an old boiler, and would not keep my house warm.

Thank you very much for the detailed response and guidance.

I believe it truly is a draught, as during the days you can feel some movement when its windy, and with the lack of proper sound isolation there is definatley something dodgy! Ive ordered some smoke pencils to check, they will be here at the weekend. We've also got a gas fire and therefore open flue, so that should be causing some additional air movement even when its not in use (which isn't often).

I have checked the downpipes / gutters, they all look good above ground.

Unfortunately, under the boards is something I can't easily check due to the wood flooring that was installed three days after we moved in, so looking at a boroscope to look via the airbricks that are under the dpc, but that's not likely to get me access to all areas.

Yes, I'm on a water meter, so will try a day of water being off at the stop cock and see if there is any movement in it.

As to the boiler expansion tank, I think were OK, but that's on the basis I've just been up and tied it off but it was floating high anyway as it seemed rusted shut.. Yet another thing to fix!, but we did get a leak stopper added alongside our yearly gas service a few months ago due to a minor leaking rad joint in a wall that we knew about that's been stopped.

I was looking at replacing the over bath extractor when possible as its not quite up to the job (mirror is slightly steamed up) .. Ah, some additional moisture will be from towels drying in the bathroom.

As to the gas usage, the rest of the house stays nice and warm, apart from 2 rooms. This might have something to do with a 8 year old 50" plasma in the living room...

As vents are needed in the roof, I'm assuming that tile vents are easier to fit than gable end air vents, but which is more effective?