DIY external wall insulation - bodge job....

[JP_]

OK, so here's my bungalow.
Red marks areas where there has been damp and mould - presumed condensation due to cold walls.
Blue is where I am planning to have some internal insulation added as part of a refurb.
Green is where I am thinking of adding a little external insulation myself.

The reason why is because this is withing an enclosed porch, the insulation will be within a recess each side. Want to avoid insulating the internal walls adjacent to the porch as it will take up vital floorspace (I won't get all my furniture in if I reduce that wall by 10cm.

As this area is weather tight already, and it's just a small part, I was thinking of just cutting 100mm board to size, shoving it in, and sealing with expanding foam. Then paint over. One side is obscured with shelving for boots etc. so nobody will see it.

Should I still consider adding anything else, such as additional vapour barrier, or anything? As I say, i know its a bit of a bodge job, but it should cut down some of the cold walls.

I have thought about full external insulation too. But costs just seem too high. I'm not bothered with doing anything in the dining room for now.

 

[JohnD]

A surprising amount of condensation, and well away from the kitchen and bathroom. To test if it is condensation (or, say, a roof or gutter leak), tape a piece of clear plastic tightly to the wall. If mist and water form on the room side, it's condensation. If on the wall side, it's a wet wall.

I'm wondering where all this water is coming from.

Do you have cavity walls?

When do you open the windows?

Does anyone drape wet washing indoors? Which rooms?

have you got a concrete floor?

where are the drains running? especially a rainwater gulley on that side?

presumably the watermain comes in near the kitchen and bathroom side.

 

[Nige F]

All good points from John + do you have a kitchen and bathroom extractor ?

 

[JP_]

Well, it is historic mould - all from previous resident. All restricted to corners, mostly.
One extractor fan in the bathroom, none in the kitchen (I'll be adding one). Water mains comes up in kitchen.
A single, limited look under the floor saw that it was dry. And wall looks dry externally too.
When we moved in, the oven was broken and she left a portable electric hob - i think she boiled everything.
Plus, very musty house.
I am hoping it won't be anywhere near so bad, but also do not want to risk damp and mould getting into clothes and books, which will be in bookcases on some external walls. So some improvements required.

But, one drainpipe does run down the front corner that has had mould. I did wonder about that. I am planning to take a look down there soon, once the new bookcase is ready to be moved.

 

[JohnD]

I'd try the plastic straight away. Perhaps the problem has stopped.

Some people like to drape wet washing over radiators, which is a common source of condensation. Maybe the previous occupant didn't open the windows.

If you have cavity walls, and no defects such as cracks and bad pointing, CWI may be surprisingly cheap and give a big improvement.

 

[JP_]

Not cavity walls, just solid walls with pebble dash, that's been painted, pink....

Maybe we don't need to do anything ... it was chilly out this morning, and the house was warm enough. Maybe she also never put the heating on. I have already decided to keep it on 24/7, at a lower temperature at night. That will probably be cheaper than full renovation!