Isulating solid concrete house

[AlQ]

Hi All and happy new year!
I have just bought a 1960's solid concrete house, it is end of terrace and the hall stairs and landing are on the end wall (which faces east) which is very cold. There is no damp, just a small amount of black mould which cleared up when the wall paper was stipped off, possibly due to condensation?
I have read some of the posts on here which has proved to be informative but not quite specific to my question.
I want to insulate the end wall internally, can I fix polystyrene backed plasterboard direct to the internal wall? I intend to screw the boards onto the wall and use a joint filler then paint the boards. I would like to stay within the closed string of the staircase to preserve the width of the stairway. I have approx 24mm to play with.
Was thinking of 12.5 mm board with up to 10mm polystyrene backing.

Any help would be much appreciated.

 

[alittlerespect]

Your wasting your time, you would be better off exploring the options for adding an external insulation system and clad the whole East elevation while your at it you may as well consider any other exposed areas and get the job over and done with in one go!

for example 10mm of polystyrene insulation will give you a U value of around 3, that's right 3 whereas 100mm of insulation will give you a U value of around .3 If you go for 50mm of polystyrene insulation you will end up with a U value of around .6 In comparison if you went with a PIR insulation material you would get the following results 100mm thickness = 0.24; 80mm = 0.3; 50mm = 0.48; 10mm = 2.4 In this example you could substitute 100mm thickness of polystyrene with 80mm PIR and obtain the same U value (0.30W/m2K) but you do not have 80mm to spare hence the reason for proposing external insulation in your particular circumstances.

Regards

 

[AlQ]

DSXekmC4

Hi All. Thank you for the advice 'alittlerespect'. I went ahead and used a plaster board with 12 mm of polystyrene back and a 9.5 mm board. I screwed it direct to the wall. So far, the heating has stayed off over night and the hall stairs and landing are so much warmer. The total cost breakdown was 110 GBP for 10 boards and pennies for screws and plugs from screwfix. Took approximately four hours to do (by myself) and was less than the cost of the planning application alone that would be needed to do the suggested work on the outside. I have been checking for any signs of moisture (its been a month already) and so far none. Going ahead with the tape and jointing this weekend.
Dont mean to be derogatory or anything but its worked well so far and saved me a packet in heating.

 

[mointainwalker]

Can you say who produces the board you bought I ask because it sounds like a crazy spec that I would have thought totally unmarketable.

 

[AlQ]

Hi Mountain walker.
I am afraid I am unable to help you with specifications. U values and insulation ratings are a mystery to me and there is no brand name on the board I used. I got it from a local builders merchants in south wales. Its a 9.5mm board with 12.5mm of polystyrene on the back.
I only tried it out because I needed a compact, quick and more importantly cheap way to insulate the wall.
I went for polystyrene because it seems to have good heat reflecting properties. For example just get a bit of polystyrene packaging and hold it in your hand, it will feel warm. This is not heat coming from the polystyrene but heat reflected from your hand.
At the risk of getting more U values quoted at me by people in the know, I am an electrician and work on building sites, lots of polystyrene insulation going on.
Hope this is some help to you. Like I said, despite the U values, its worked a treat.

Al Q

 

[noseall]

Hope this is some help to you. Like I said, despite the U values, its worked a treat.

Al Q

Well there you go.

All you celotex and kingspan worshipers, hold your heads in shame.

There is no point in shelling out for decent stuff when 12.5mm, YES 12.5mm of polystyrene will do the job!

 

[freddiemercurystwin]

 

[drnail]

12.5 poly aint thick enought to insulate me fish tank

 

[alittlerespect]

Well! Like they say the proof of the pudding is in the cooking!! And unless you put your toe in the water your not going to know how cold it is and likewise insulation - your not going to know how good it is unless you try some!!

I'm glad to know that it worked for you AIQ.

Just stepping into U values - you will have improved the heat loss through the wall from a value of around 2.13W/m2C (that is the rate of heat loss in watts per m2 per degree C temperature difference) to around 1.15W/m2C hence the reason you are feeling the benefit! and Good Luck to you.

However, assuming you had gone for say 50mm of polystyrene your heat loss would have been reduced to around 0.53W/m2C - or less depending on the thermal conductivity of the material that is used. This is not meant to be a criticism of you I just thought that it may be useful information for others reading this thread. As a final note if you incur Building Regs the target U value is 0.35W/m2C.

Regards