Claymaster - any advantage of using a thicker sheet

[Viral0]

Building inspector has recommended using claymaster on inside wall of foundations, they've only specified a minimum of 50mm thickness. Would there be any advantage of getting a thicker sheet of lets say 75mm or even 100mm.

It's a clay soil foundation set at 1m deep. One corner of the foundation is within 4 metres of a large horse chestnut tree, therefore at this corner 2metres each way the foundation has been dug to 1.5m deep. This is for a double storey extension with underfloor heating, not sure if any of this info will have an effect on the thickness of boards to be used.

Any help would be appreciated as will be purchasing the boards today.

 

[RonnyRaygun]

Building inspector has recommended using claymaster on inside wall of foundations, they've only specified a minimum of 50mm thickness. Would there be any advantage of getting a thicker sheet of lets say 75mm or even 100mm.

It's a clay soil foundation set at 1m deep. One corner of the foundation is within 4 metres of a large horse chestnut tree, therefore at this corner 2metres each way the foundation has been dug to 1.5m deep. This is for a double storey extension with underfloor heating, not sure if any of this info will have an effect on the thickness of boards to be used.

Any help would be appreciated as will be purchasing the boards today.

No, no advantage. Thickness of claymaster required depends on the shrinkability of the soil, so provided your soil is medium shrinkage then 50mm Claymaster is correct.

However, you don't actually need Claymaster until the foundations are more than 1.5m deep, so you shouldn't need any.

 

[Viral0]

Thank you for the info, am not entirely sure of the soil shrinkage so am opting for a 75mm board just to be safe, cost difference between 50mm and 75mm is only £90 for 25m square of foundation. Again thanks for the reply.