damp/cold coming from the terraced alleyway below

[ambercelery]

hi

i have a 1960's ex council terraced house. One side of the house is fully joined to the neighbours, the other is only joined by the upper floor. There is an alleyway to both backgardens.

Above the alleyway of about 1m width, half of the area is part of my house and part is my neighbours. my house is usually warm. Has cavity wall and good loft insulation - but my two rooms that have a bit of the alleyway below are much colder and smell a bit like damp.
There are no other areas of damp.

I have lifted the carpet and above where the alleyway is, i have normal floorboaards but these are just sat on a big concrete slab (i.e. I.m guessing the ceiling of the alleyway). There is no room to put aanything down underneath the floor boards.

Do you have any suggestions on how to insulate this concrete slab below my floor boards as some of the boards feel pretty cold/damp causing the smell

 

[alittlerespect]

Hi

Consider using PIR insulation to the external sophet, use adhesive with occassional screw fixings. Ideally you should use a 100mm thickness but 50mm will also give added benefit.

To finish, tape and joint and finish with external masonary paint - job done!

It will take some time for the floor to warm up as an added benefit the PIR insulation will put the condensation zone outside of the construction and you should have no further problem with the damp smell, but it won't clear up overnight!

Regards