New cavity wall - insulate or not?

[str]

I'm in the process of having a side extension built and the architects specified a cavity wall of concrete bloock to both inner and outer walls (although the front elevatin will have an outer skin of sandstone).

However, there is now mention of any insulation within the cavity and i am now worried that I should have had this installed whilst the walls were being built

will i have any issues with not have cavity insulation, in terms of colder rooms?

thanks

 

[regsmyth]

I'd be suprised if no insulation was required.
What does the architect say?

 

[cmother1]

Even more important what does the the Building Control Officer say? Didn't your local planning office approve a plan which specified how the wall would be constructed. I'd be amazed if you could get away without specifying insulation nowadays. I'd have thought that a Thermalite wall without insulation would now need to be about 15" thick. Not very pretty.

 

[str]

have yet to query with the architect

its not a thermalite block, they are concrete blocks (7N/mm2)

 

[jeds]

Yes you should have built the insulation in. If it was not mentioned on the architects specification that was an error. With an internal skin of medium density concrete block it will now be quite difficult to achieve the minimum U-value. Cavity wall injection will get somewhere close but I don't think it will be enough on it's own. Has the building inspector not seen it yet?

I'm also suprised that a builder would carry on and build a wall with no insulation and not mention it. Even the most dinasaur builders have now twigged to the idea that how they used to do it in the 70s is no longer acceptable.

 

[r896neo]

good quality platinum bead cavity wall insulation should be enough to satisfy building control.

 

[noseall]

good quality platinum bead cavity wall insulation should be enough to satisfy building control.

Eh? Platinum what?

 

[noseall]

I'm in the process of having a side extension built and the architects specified a cavity wall

I find it very difficult to believe that an architect did not specify cavity insulation. I think it incredulous that a builder would proceed and actually build without cavity fill.

Did you remind the builder to eat and take a pee?

 

[noseall]

Did the architect specify tie wires, mortar, dpc?

 

[freddiemercurystwin]

Somethings tells me we're not being told quite the whole story here.

 

[noseall]

Somethings tells me we're not being told quite the whole story here.

No kidding.

Care for a ride......

 

[joe-90]

Did the architect specify tie wires, mortar, dpc?

No but he specified concrete block to take the weight of the joists.

 

[str]

not sure whayt parts of the story I'm not telling?!

The ground floor is only a garage, so I'm not concerned about that but the 1st floor will be a bedroom - there is insulation specificed for when the inner wall is strapped out for plaster boarding and insulation within the roof void and also floor void but I was starting to get concerned that the cavity should also be filled?

 

[regsmyth]

You would normally only use insulation if the space was to be heated, so it sounds like you will have an uninsulated, unheated garage, and an insulated, heated bedroom, so it sounds fine to me.
However you should make sure that the insulation is continuous, esp where wall ins meets floor ins, and where wall ins meets ceiling/roof ins. Gaps will lead to cold spots and internal condensation.

 

[noseall]

We fill all (unheated space) cavities whether it be a garage wall or a gable end.