Insulating a door - help

Captainmouse

I moved last autumn to a house with good insulation and double glazing. Reasonably draught free and well maintained. But, both the front and back door are just normal wooden plank doors, with a protruding Z. The front door has a small porch with another door to the hall. This I have hung a curtain hallside and put a draught excluder at the bottom. There is no heat source in the porch.

The back door comes into a rear hall with doors leading to the shower room, utility room and kitchen. I leave a small window open during the day for the cat. There is a small radiator. Last winter I hung coats on the back of the door, but was horrified to discover this was trapping condensation and causing mould. I removed the coats, and cleaned the mould.

There are vents above all the windows which I have had open during the warmer weather. Now it is turning cold I have closed the vents round the house, the rear window is still open during the day. This morning was particularly cold and I discovered condensation on the inside of both doors.

How can I insulate the doors? Can I put space blanket against the doors in the recesses and cover with board? Would hanging a curtain cause the same situation as the coats?

Searching the net only talks about gaps round the doors.

Captainmouse

Anybody??:(

ic

My grandparents have a similar style back door to what you describe. I used a window film kit on the window (also on all their other windows around the house) and draught strip around the gap. I keep wondering whether to get some polystyrene sheets (B&Q do them very cheap), cut to fit the triangular gaps, and then nail over a piece of hardboard. Not sure how effective that might be, I just keep thinking about it.

Captainmouse

Thanks for that, there are no windows in either of the doors, there are no gaps around the doors they are a good fit, the only draught is through the keyhole.

I was shocked at how cold the actual doors are, I have never experienced condensation on doors before.

teneighty

I've got the same type of framed ledged and braced door.

I'm considering infilling between the "Z" as you describe it with rigid foam insulation, kingspan, celotex or similar (about 25mm thick) and then covering the inside with new tongued and grooved timber, about 9mm thick.

I haven't got around to it yet but I cannot see any reason why it wouldn't work. Although you would need to check if you could increase the thickness of the door without it catching on the frame when it opens, should be fine though.

Captainmouse

Wood the silver coated poly sheets that are designed to go behind radiators be any good?

Ken68

My guess, and I havn't yet gone into it fully, is to move the dew point to the outside of the door.

Captainmouse

Translation please?

Ken68

An exterior door curtain or as I am thinking of doing here, cover the insect screen door with polythene or whatever.
The insect door (home made, and not difficult) is normally put into the garage for the winter.
I have cured the condensation on some of my downstairs windows by inserting a 50mm polystyrene slab into the reveal on the outside.
These were free and probably not economical if you have to buy.
BUT they do work, so presume anything hung or placed on the outside makes an impact on the temperture difference,so altering the dew point.
Try it yourself on a small window, it will work.