Condensation forming puddles on bitument in extention

[DJHicks]

Hi all. I'm in desperate need of advice please and want to thank anyone that can advise anything in advance!

I have single brick (what used to be) a porch and storage room at the back of the house. It used to get damp in the at the back bottom right and left corners...

I wanted to make the room functional but being so small i couldn't make a room within a room if you get me so I battened the walls and put plasterboard up. Both not touching the floor.

I had carpet tiles on the floor and then underlay and carpet on top cut so it was just under the plasterboard.. or so i thought.. the bottom right corner a friend cut but too long so it was touching the wall, soaked up water/moisture and that rose up the plasterboard as it would.

I'm changing the room use and got rid of the affected plasterboard, carpet and underlay.....

I put bitumen on the area that was getting slightly damp and left the plasterboard off to keep an eye on it... and it seemed to do the trick!

I had a radiator plumbed into the room as it used to go below freezing im sure! Obviously where cold meets hot you get a dew point and thought it'd put some bitumen along the bottom of the walls as I could not see a dpm layer under the bottom brick.




My issue now is the bitumen being rubber gets so cold because of the wall and floor when the warm air hits it, it is condensing. if i breathed on it, it'd go pale like a window steaming up etc.

Now i have insulated the ceiling and plaster boarded that, then coved along the top, the only way air can travel around(and there is a slight draft) is to come down the walls and under where the plasterboard doesn't touch the floor into the room which then hit the heat... or vice versa the heat goes undder the baords and up the wall thus condensation on the walls etc.

This condensation forms an runs to the floor forming small puddles!

I have spoken to a few people but they have given out rubbish advice in the past so wanted to ask a collective of people please for advice.

My father has suggested that once I put the skirting on, lay the vinyl flooring and seal it I will stop or greatly reduce the cold air meeting the cold air thus stopping or again greatly reducing the condensation.

Any advice on this at all? Shall I remove the bitumen from the bottom of the walls (bolded above), except the main damp corner?

Thanks again!![/b]

 

[noseall]

You have done everything but insulate the problem area....WHY!

 

[DJHicks]

The main reason for not insulating the walls is that room is less then 2 metres wide, with the battons and plasterboard obviously now even thinner obviously.

With the plasterboard off the ground thus a gap between the floor and wall would this still not be happening even with the insulation? as air can still travel as it now?

It appears to only be happening on the left and rear wall where the plasterboard is cut a little higher then the right by about a cm or so. allowing more airflow I suppose.

Its weird though, yesterday morning there were the very small puddles but last night when i actually when to dry them up with some kitchen towel they were hardly wet at all. Again only on the left and rear walls...
I would have thought with the outside temp drop being late evening it would be worse as the heating was on so still maintaining the temp inside as it was all day etc.

The walls it happens on are the walls the sun hits....

Thanks

 

[JohnD]

you need a vapour barrier to prevent the warm, moist indoor air touching the cold surfaces. This barrier should be on the room side of your insulation. You might like to look at the Kingspan or similar bonded plasterboard:insulating foam

You will have to seal all joints to stop the warm damp air getting behind it.

Also ventilate this room to the outside, and use a close-fitting door to reduce moist air from the house getting in.