Here you can find the rough costs of materials used for this extension. Before purchasing you can try negotiate prices with your local builder merchant by showing them the plans.
BRICKS & BLOCKS
Engineering bricks 65mm £0.30 each
Engineering bricks 73mm (imperial) £0.50 each
Concrete blocks 100mm 7n £0.75 each
Thermal Blocks 100mm £1.00 each , usually 72 in a pack
Air brick £3.75 each
Ibstock Multi-rustic 73mm bricks £.50 each
AGGREGATES Jumbo bags are also called one ton.
Cement bag £2.85 standard, £4.20 premium
Jumbo bag building sand £32.00
Jumbo bag ballast £30.00
Jumbo bag hardcore £28.00
Jumbo bag sharp sand/screeding sand £?
Roof laths 16ft £1.92 each, usually 10 in a pack
4 x 2 16ft £5.60 each
5 x 2 16ft C16 grade £8.64 each
4 x 4 10ft £9.50