Condensation on ceiling by front door

[StudWall]

Hello

i live in a 50-60s bungalow and i'm having a problem with condensation forming on the bit of ceiling near the front door.

Above the front door is, what appears to be, a solid concrete slab which is parallel to the front door and at 45 degrees to the joining walls, which is flat above, ie not part of the ordinary pitched roof, which makes it impossible to insulate?

i have sealed up around the front door to make sure there are no cold draughts and have also applied several layers of bitumen paint to the top of the concrete block, in case water seeping through was the issue.

Having the heating on eventually gets rid of it, but it comes back so easily that if the heating is off for more than a couple of hours it starts to get wet again.

has anyone got any ideas of what i can do, all i can think of is to install a pitched roof over the flat to allow me to insulate it ?!

 

[cjard]

Pics might help. To form condensation you need warm moist air coming into contact with a surface that is 12, maybe 14 degrees centigrade or lower. Depending on what you do in the house (run a gas fire, dry all your washing on radiators, boil the kettle often, breathe a lot, shower in a room with no working extractor etc) you might have a very moist internal air, and no strategy to deal with it. Heating doesn't necessatily help, as warming the air will only ensure it can hold more evaporated moisture. It'll atill condense on a cold surface

Does this area condense up in hot summers too? It still rains in summer y see, so if it's a leak, it will be wet independently of the temperature. If it's condensation it will likely be worse in winter. As to what you can do about it, reduce the moisture content of the air or increase the temperature of the surface so it's no longer a condensation risk

 

[StudWall]

Its definitely a condensation issue because its fine in warmer weather and rain.

I dont dry anything indoors and no gas except boiler, fire is a wood stove. I have good extraction in bathroom and kitchen and don't get condensation anywhere else except a bit of misting on the windows.

 

[John D v2.0]

Yes pics would definitely help, or even diagrams.

If it is how I imagine, you have 2 choices. One is insulate all outside surfaces of the concrete with celotex and render or flat roofing/a pitched roof. Perhaps what you're suggesting.
The other, which is probably better due to the thermal mass of a concrete roof, is to insulate the inside ceiling (edited!), at least the area that's cold.
You can get an ir thermometer online for less than 20 pounds which is really useful to find the profile of temperatures.

Oh and I suppose the final option is to knock the concrete down and then the problem becomes simpler, but I'm guessing that's not practical.

 

[^woody^]

Put a piece of insulation on the ceiling

Sempatap or 10mm celotex

 

[StudWall]

Ok heres how things look from the inside

IMG_20161111_103008

• StudWall
• 11 Nov 2016

you can see the step down in ceiling height towards the front door, that is soild (i assume concrete) plastered over.

from the outside:

IMG_20161111_103404

• StudWall
• 11 Nov 2016

IMG_20161111_103415

• StudWall
• 11 Nov 2016

 

[JohnD]

(i assume concrete)

very improbable.

Is it a flat roof? Can you stand back and show more of the roof shape?

Much more likely that it is a bit of flat roof that was not insulated when the bungalow was built, and has no access so was neglected when the loft was insulated to modern standards.

If that bit of flat roof is due for renewal soon, you could have the old deck taken up and insulated from above, otherwise you could have the ceiling taken down (pretty sure it will be plasterboard on timber joists) and insulated from below.

Woody's idea of applying an insulating slab to the ceiling will be the easiest and cheapest option. An experienced plasterer could do it, but you would lose ceiling height. 30mm at least, though thicker insulation would give better results, your door would hit it.

 

[StudWall]

here's a picture from above:

IMG_20161111_112505

• StudWall
• 11 Nov 2016

Im sure its a solid block, it definitely feels it from the top, bottom, and sides.
If there is a void in there somewhere then ive no idea how to get to it!