Selecting a roofer

[robinbanks]

Had a chat with checkatrade

Oh no

Venting plus a dehumidifier has solved it

Sounds like your life habits might be putting too much moisture in the air in the first place..

he just took some pictures from the outside

maybe lacked the brain cell count required for drone pilotry

 

[Phil473]

Oh no

We regulary vent, run a dehumidifier. These houses are prone to condensation once double glazing has been installed and chimneys sealed.

I get that checkatrade aren't the best, but what else is there? Any reliable roof federations with reliable members?

 

[robinbanks]

These houses are prone to condensation once double glazing has been installed and chimneys sealed.

No house is prone to condensation unless humans live there. Nothing about a building intrinsically generates airborne moisture

If you've installed more airtight windows and blocked the chimney, then you've potentially considerably cut down the amount of background ventilation the property previously enjoyed. If you've then carried on with lengthy hot showers, boiling to cook things, drying washing on radiators, having tumble dryers that don't vent well to outside, lots of plants, or even just having lots of people in the house you've got the same moisture loading going on but a cut in the background venting means your inner humidity is higher. Couple it up with colder weather, lower ambient temps and it's a condensation generator as the external surfaces are cool

The solution to it all is to strive for balance; the moisture that goes into the air needs to stay there til it's outside the building, and some measure of reducing the moisture, or increasing the temperature and/or ventilation is required

 

[Phil473]

My understanding is that 1930's houses were designed with single glazed windows in mind, so the switch to double glazing produced potential condensation issues.

 

[Phil473]

No house is prone to condensation unless humans live there. Nothing about a building intrinsically generates airborne moisture

If you've installed more airtight windows and blocked the chimney, then you've potentially considerably cut down the amount of background ventilation the property previously enjoyed. If you've then carried on with lengthy hot showers, boiling to cook things, drying washing on radiators, having tumble dryers that don't vent well to outside, lots of plants, or even just having lots of people in the house you've got the same moisture loading going on but a cut in the background venting means your inner humidity is higher. Couple it up with colder weather, lower ambient temps and it's a condensation generator as the external surfaces are cool

The solution to it all is to strive for balance; the moisture that goes into the air needs to stay there til it's outside the building, and some measure of reducing the moisture, or increasing the temperature and/or ventilation is required

The new roof will have a breathable underlay. How breathable are these underlays exactly?

 

[robinbanks]

Should be in the manufacturers spec sheet, but suffice to say if you do have a problem with loft condensation already, expect to see it collecting on the underside of the membrane

 

[noseall]

My understanding is that 1930's houses were designed with single glazed windows in mind, so the switch to double glazing produced potential condensation issues.

Occupied houses always produce condensation. Modern materials are just better at trapping it in, hence ventilation and insulation upgrades etc.

 

[Harry Bloomfield]

My understanding is that 1930's houses were designed with single glazed windows in mind, so the switch to double glazing produced potential condensation issues.

That is simply untrue. 1930's house were built with single glazing, because double glazing simply wasn't available then. Homes then, relied up on lots of heat going into them, in limited areas, and lots of air flow. Now, we heat the entire home, and try our best to keep that heat in place by sealing the house up. To get away with that, we need to minimise the generation of moisture indoors, and where it is unavoidable, extract it. It works effectively, irrespective of the age of the dwelling.

 

[robinbanks]

My understanding is that 1930's houses were designed with single glazed windows in mind, so the switch to double glazing produced potential condensation issues.

It doesn't make sense. Single glazed windows present a colder surface to the room and are more effective dehumidifiers/suffer more condensation.

Double glazed windows were likely better sealed against draughts. You have to consider changing habits; once upon a time draughty windows and doors were the norm and we lit small bonfires in every room, that would flow a huge volume of room air out of the chimney, moisture generating appliances were fewer (tumble dryers not invented), and line drying clothes outside more prevalent. Building materials were more vapour open (lime plaster)
We thus had high background ventilation and lower moisture loading

Over time habits changed, but double glazing doesn't now, and has never caused condensation.. Human behavior causes it. We shut ourselves in more airtight boxes, generate loads of moisture and then complain when things go mouldy. We are unsurprised when the half eaten sandwiches and bashed up fruit in the kids' lunchboxes does the same thing when left at school over the holidays. Common sense is uncommon

 

[blup]

The roofer I mentioned above actually was recommended by a neighbour. Neighbours flat roof has been fine, mine leaked 3 times.

Existing problem has been with new cement and flashing, to base of chimney, on pitched roof. Had it done last year, failed this year. I'll try and get roofer to put it right, as it shouldn't fail this early.

As the roof may be the original 100 year old roof, I may well just get a new roof. Otherwise, the repairs are going to mount up.

Replacing the roof is using a sledge hammer to crack a nut. Identify the cause and work from there. Posting some pics will get you practical help on the potential issues.