On 9 May, 09:08, wrote:
We are having an extension built, and at the same time recasting our
double garage as a "family room". These two, together with the
existing kitchen, will be floored in Karndean (yeah, I know, very
expensive, but what can you do? I'm planning to buy it on-line
reduced and lay it myself.)

So, my question is underfloor heating - is it worth it, and if so, are
there any makes or systems that stand out? I'm not looking for
bargain basement, but I am looking for reasonable value for money.

I called Karndean and asked them about the preferred substrate for the
floor. The girl in technical services told me that I would need to
lay a reinforced screed of a minimum of 67mm.

So, I talked to a friend who had UFH and he said he'd never heard of
67mm - he had used 75mm for insulation, and 75mm for screen. So I
called Karndean again.

(Me) "This 67mm reinforced screed - are you sure about that?"

(Same girl) "I'll just consult my colleague ... yes, that's right."

(Me) "It's just that 67mm is such a weird value - most people I've
talked to have mentioned 75mm"

(Girl) "No, not 67mm, 627mm!"

(Me) "Six hundred and twenty seven millimetres? Are you having a
laugh?"

(Girl) "No, 6 to 7 mm"

(Me) "You mean between 6 and 7 mm?"

(Girl) "Yes"

(Me) "Then why didn't you say so"

Ted.