Breeze block or thermal insulation board?- HELP PLEASE!

[spaceryder]

I am having a kitchen and garage extension built and for the wall in-between the kitchen and garage, the plans indicate a wall consisting of two layers of breeze block with insulation in-between.

Now, the builder is adamant that all I need is one layer of breeze block (black) which he has built and that I will get the same level of insulation with some thermal board on the outside and no need for another a layer of breeze block as this will give me more space in the garage.

My questions are:

1 Is the builder telling the truth, and if so,
2What thickness of insulating board would I need?

Many thanks in advance as I need to tell him within 48hrs.

 

[tony1851]

My questions are:

1 Is the builder telling the truth, and if so,
2What thickness of insulating board would I need?

1. Yes,
2. Probably something like 50-75mm.

 

[theprinceofdarkness]

A garage next to or under living accomadation should be properly fireproofed. So if you only have one skin of breeze block you must have heat insulation and an extra fire rated layer. It could still work out cheaper?
Frank