If I can't heat my house, how do I stop damp?

[babysoupdragon2]

We live in a 1930s semi.

Every winter we have huge issues with condensation on the windows, I have to do a daily window vac otherwise it spreads to the walls. This is despite ventilating the rooms well. No other damp causes.

The only thing we've found to help is to not let the temperature drop below about 15 overnight. But there's no way we will be able to pay for this this year.

Anyone have any suggestions?

I understand now if it’s the west! 🙂

@ohholyday we haven’t used the dehumidifier since may,our electric usage only went down by £3 a month.

My council house is over 100 years old. Every winter is the same, condensation and mould no matter what we did. The council came round, lifted up the floor boards and there's no ventilation(?) blocks underneath which is common in old houses so all the flooring needs to be ripped up and blocks put in as we have rising damp

In regards to a dehumidifier, buy the biggest one you can afford. You're going to need it

Someone very very good at maths would have to work out whether heating a house to 15 degrees or running a dehumidifier is cheaper

We have the same issue with our mid terrace built in 1900.

@Wearefoooked22 , it's definitely going to be using more than £3 a month. I looked the brand up on Curry's website where it says the low energy ones are 157 watts and then imput that into the calculator I linked to.

There are a few ways you can reduce condensation in the property including, making sure you're using your bathroom/kitchen extractor fan and if you don't have one getting one installed will reduce the amount of moisture in the property.

Another way to reduce condensation is to make sure your washer and dryer is correctly vented to the outside as these can cause excess moisture to build up i the property.

Unfortunately dehumidifiers are a short-term solution to condensation and don't provide a whole home solution. There are systems that can provide a full solution and prevent mould growth, these are called Positive Input Ventilation (PIV) systems.

Windows open everyday and plenty of airflow.

I have the same problem here in 1940’s property, in spring I cleaned walls, used a damp paint and then repainted. On some exterior walls I used a brick sealant to repel water.

we put heating on on Nov 1st usually in evening only, by 18th we’ve mould patches on the walls next to window frames

i have a 360 aero plastic thing with tablet in each bedroom.

Am considering a MVHR system (mechanical ventilation heat recovery) I’ve no idea how this compares to a PIV (positive input ventilation) system that others have mentioned - does anyone have it? My only concern is some Google searches advise they are more efficient in newer build houses where insulation is much more tight - I feel we have to do something long term as now we have made the decision not to move I am not fancying damp painting walls and repainting every spring ready for them to face the next winter!

@EveSix

What kind of insulation goes on the outside?

Also how did that affect house in heat?

I used to have loads of these in the old Victorian rental properties I lived in in London. The letting agents would always send out ‘damp guidance’ that basically amounted to - ‘open the windows and keep the heating on and if you don’t it’s your fault if you get damp’.

www.robertdyas.co.uk/unibond-aero-360-pure-moisture-absorber-dehumidifier

These are non-electric dehumidifiers, I found one in each room worked a treat and stopped me from getting chest infections that I get from damp environments.

External insulation uses blocks of polystyrene or wool to wrap around the outside of the house. They are then rendered over. We have it on our 150 year old house with no cavity walls. It means the walls retain the heat coming from the house and the warmer walls mean no air condensing there creating mould.

It's not a cheap option by any means. We have such old housing stock in this country. I wish there was more help available for people to have improvements like this done to their homes.

The heating hasn't been on in my bedroom and humidity was around 80! Since I have had the radiator on for an hour in the morning and 2 hours in the evening it's dropped to 50- 60. I know heating is expensive but make sure even if it's only for an hour there's some heat in the room.

PuddyWoodyCat, our exterior insulation consists of high density phenolic insulation foam boards which have been bonded to the outside walls and rendered over, as eurochick explains (thank you). It took about a week to fit and required a scaffold all around the house. The board is bonded to the old render, if sound, with pins and resin, and soffits, fascias, external pipes and cills are replaced as the house technically becomes a little bit bigger on the outside.
This year, we have only turned our heating on for half an hour this evening, having relied on our woodburner until now, and it has been sufficient to keep us warm enough, without any major condensation.
We paid for ours privately, but the council did all of their own stock on our estate and it's transformed comfort and standard of living for many of our neighbours.
Insulate Britain have been unfairly vilified for suggesting schemes like this should be rolled out more widely. It is an absolute no-brainer to me, we have benefited SO much from our insulation since the day it was put on.