Kumar IronUpdated
In this guide
Standard sizes
AAC blocks are covered by IS 2185 (Part 3). The standard includes block lengths of 400 to 625 mm and heights of 200 or 100 mm. In practice the block most sold in north India is 600 mm long and 200 mm high, with thickness from 75 mm up to 300 mm depending on the wall. Fly ash bricks follow IS 12894, and the common size is 230 x 110 x 75 mm, with some makers using 70 mm height or a slightly smaller brick.
| Block | Size | Typical use |
|---|---|---|
| AAC 100 mm | 600 x 200 x 100 | Partition walls, internal |
| AAC 150 mm | 600 x 200 x 150 | Light partitions, some outer walls |
| AAC 200 mm | 600 x 200 x 200 | External infill walls |
| AAC 230 mm | 600 x 200 x 230 | 9 inch outer walls |
| AAC 300 mm | 600 x 200 x 300 | Special thick walls |
| Fly ash brick | 230 x 110 x 75 | Walls, boundary walls, load bearing small houses |
Always check the size on the delivery. Ask the seller for the dimensions and the density class, since lengths, widths and thicknesses may differ by brand.
Approximate weight per block
AAC density is usually given as oven dry density. Many makers of 600 x 200 blocks quote about 551 to 650 kg per cubic metre. Weight = volume x density. The table uses 550 to 650 as the range. Blocks on site hold some moisture, so the real weight is somewhat higher, and the label of the maker is the best guide.
| Block (mm) | Volume (m3) | Approx weight (kg) |
|---|---|---|
| 600 x 200 x 100 | 0.012 | 6.6 to 7.8 |
| 600 x 200 x 150 | 0.018 | 9.9 to 11.7 |
| 600 x 200 x 200 | 0.024 | 13.2 to 15.6 |
| 600 x 200 x 230 | 0.0276 | 15.2 to 17.9 |
| 600 x 200 x 300 | 0.036 | 19.8 to 23.4 |
A fly ash brick of 230 x 110 x 75 mm has a volume of about 0.0019 cubic metre. At a typical density of 1500 to 1700 kg per cubic metre, that is roughly 2.9 to 3.2 kg. Many makers quote about 3 kg per brick, so 1000 bricks weigh about 3 tonnes. A truck load is limited by weight, so plan trips accordingly.
Blocks per square foot and per cubic metre
For AAC 600 x 200, the face covers 0.12 square metre, which is 1.29 square foot. So one square foot of wall needs about 0.77 blocks, or about 77 blocks for 100 sq ft, before wastage. Per cubic metre of finished wall, a 600 x 200 x 200 block gives 1 / 0.024 = about 41.7 blocks. Per square metre of wall face it is about 8.3 blocks, whatever the thickness.
For fly ash bricks, with a 10 mm mortar joint the effective brick is about 240 x 120 x 85 mm, a volume of 0.00245 cubic metre. That gives about 408 bricks per cubic metre of wall. For a half brick (4.5 inch) wall, the face area per brick is about 0.0204 square metre (240 x 85), so you need about 4.5 bricks per sq ft of wall. A 9 inch wall uses about twice that.
| Wall | Per sq ft of wall face | Per 100 sq ft |
|---|---|---|
| AAC 600 x 200 (any thickness) | 0.77 | 77 |
| Fly ash brick, half brick wall | 4.5 | About 455 |
| Fly ash brick, 9 inch wall | 9.1 | About 910 |
Where each one is used
- AAC 100 and 150 mm: internal partitions, bathrooms, light dividing walls.
- AAC 200 mm: external infill walls in RCC framed buildings.
- AAC 230 to 300 mm: thicker outer walls where more insulation is needed.
- Fly ash bricks: walls up to the usual house height, boundary walls above the plinth, and load bearing walls in low rise homes where the design allows.
- Neither is a good pick for below ground or damp locations without a damp proof course and care.
Ordering tips
Know the size and thickness your drawing needs, then ask for the density and strength class. Our AAC block calculator works out the number of blocks and mortar for a given wall. For laying, use jointing mortar as explained in our laying guide. Rates change often, so call or WhatsApp for today's price and delivery.
Frequently asked questions
- What is the standard size of an AAC block?
- The most common is 600 mm long and 200 mm high, with thickness from 75 to 300 mm. IS 2185 (Part 3) covers lengths of 400 to 625 mm and heights of 200 or 100 mm.
- How much does a 200 mm AAC block weigh?
- About 13 to 16 kg dry, for a 600 x 200 x 200 block at a density of 550 to 650 kg per cubic metre.
- How many fly ash bricks in a cubic metre?
- Around 400 to 410 with 10 mm joints, and about 527 if you ignore the joints. Use the joint figure for ordering.
- How many AAC blocks per cubic metre?
- About 41.7 for a 600 x 200 x 200 block, ignoring the thin joints.