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Weber Saint-Gobain - Official website of the company

Leca® Insufill


Leca® Insufill is lightweight insulation that cuts foundation time by hours. It is available in 50 litre bags, making insulated foundations which comply with Part L of the Building Regulations a simple, one man process. What is really clever about Leca® Insufill in bags is that it is stored in the bag, collected and transported in the bag, laid in the site in the bag and covered in concrete - still in the bag.

Primary Advantages

• save hours

• eliminate the cost of machinery hire

• eliminate the need for secondary polystyrene insulation in ground floor construction

• meets Building Regulations

• simply carry into restricted access sites

Leca® Insufill is the fastest and easiest method of preparing an insulated oversite for a concrete slab with added benefits:

• achieves the latest U-values

• minimal labour required

• fills oversites quickly - discharge up to 25m3 per hour through blowing vehicles

• two man operation

• no heavy site machinery required

• restricted access or difficult site conditions overcome with ease

• no sand blinding required to level oversite

• depths of up to 3m

• ideal for use on gas contaminated land


Step 1 - Lay loose fill to level up the site and lay the bags of Leca® Insufill on top
Step 2 - Continue laying the bags side by side to cover the floor area
Step 3 - Fill in any spaces with more loose fill
Step 4 - Brick bond a second layer of bags
Step 5 - Lay a 1200 gauge damp proof membrane to complete the oversite. Then lay the concrete or Weber levelling compound.