Guidance · Updated 12 October 2026
How this system works
Autoclaved aerated concrete is a lightweight block material containing small air cells. Ytong is a brand of this material. Blocks are laid as walls using the mortars, supports and details specified by the system.
Depending on the design, blocks can form load-bearing walls or enclosures. Structure, lintels, roof and services must be specified separately: choosing a block does not describe the whole home.
How it is built, step by step
- Select block type and thickness according to its role and required performance.
- Prepare the base and lay initial courses with levelling and setting out.
- Build openings, lintels, junctions and service chases following system details.
- Complete finishes, water protection, roof and services.
Advantages
- The air cells contribute to thermal insulation; final performance depends on the complete wall.
- Blocks enable walls to be built from regularly sized pieces with openings following the design.
- It can form part of a traditional or contemporary-looking house, depending on finishes.
Drawbacks and how to address them
- Check block thickness, strength and role; not all units serve the same purpose.
- Fixings for heavy items require solutions compatible with the material.
- Junctions, finishes and moisture protection need suitable workmanship.
When it might suit you
It may suit a specified aerated-concrete wall system where the company understands its details, fixings and finishes.
What the quote should include
Compare the same scope and performance. The structural material alone does not determine which offer is better.
- Design, ground assessment and foundations.
- Structure, roof and complete facade build-up.
- Insulation, windows and solutions for water, noise and fire.
- Services, finishes, transport and assembly where applicable.
- Schedule, taxes, exclusions and responsibility for each phase.