Cavity wall insulation - sheet or bead

struggling1

I'm looking at building a new house in the next 6 months.
The question I have is in relation to the best insulation to fit in the cavity i.e. the Kingspan flat sheet type, or the bead type thats blown into the cavity.

I've heard of pros & cons for both. My concern is that builders never fit the Kingspan correctly between the cavity & leave gaps between the sheets of insulation which may downgrade its performance.
On teh otherhand some people say that the bead type insulation may transfer moisture between the outer wall & the inner wall.

Any comments/suggestions based on experience on what the best type of cavity insulation would be?

stapeler

I'd favour the idea of blowing the insulation into the cavity to ensure full coverage, another advantage is a possible savings in labour costs, I've seen a few block layers lower their price a bit as they dont have to spend time installing the the insulation sheets. Talk to block layers and see if they knock 10cent a block off if you go cavity fill...

Builderwoman!

We used Warmfill bead insulation and it's brilliant. I think that the moisture thing is a myth. Not so sure that your blocklayer will give you much of a discount but it's worth asking. They certainly do not fit the Kingspan/Xtratherm correctly and if it's not done perfectly your wasting your money. You can check all the cavities with the Warmfill and they do fill every bit of your house. We got the higher performance grey beads and are very happy we did cavity fill.

struggling1

thanks for the info, will see what discount - if any - we can get with the builder ;-)