100mm Celcon HiSeven Insulating Blocks

I'm in the process of building a new extension and the plans state that I have to use 100mm Celcon HiSeven Insulating Blocks for the inner skin of the cavity wall.
Does anybody know of a cheaper non-branded equivalent (eg. Wickes)?
Thank you in advance for any help.
Philip Riding
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If it's HiSeven that's specified, then you won't get away with anything else. The only thing to do is ask your inspector if there are any alternatives which will pass his/her inspection.
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Use full fill 75mm cavity, Celcon 100mm standard and 1/2 " plasterboard on dabs to achieve similar u value for the wall.
dg

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On 15 Dec 2003 12:00:24 -0800, a particular chimpanzee named snipped-for-privacy@hotmail.com (Philip Riding) randomly hit the keyboard and produced:

Why Hi7? They are the stronger (7N) version of the normal aircrete blocks, but unless the extension is three storeys high, then normal 2.8N blocks would be adequate in most circs.
IIRC, they have the same insulation value as Celcon Standard blocks, which are the equivalent to Thermalite Shield, which have a 'k' or 'lambda' value of 0.12W/mK. If the alternatives have a 'k' value of this or lower, then they will be just as acceptable.
--
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