Blocklaying on raft foundation

[Shorty69664]

Hi guys,

How soon after the raft has been completed can you start blocklaying?
The foundation was completed on Friday and the builder says he will be back in two weeks to start the blocks.
Is this a bit early? Will the foundation be ok to take the weight of the blocks after 18 days?
Any advice welcome...

 

[monascribe18]

wae the raft reinforced ?

 

[Shorty69664]

Yes... He has reinforced with steel as per the engineers design.

 

[Teatime]

I was told 2 weeks when I built. When they blocks do arrive, they come in bales of 40 and they are put straight onto the raft usually.

The concrete spec these days are 30-35N which is very strong and probably overkill. Should be fine in 2/3 weeks but it is icy, not sure that helps.

 

[jab1]

we started blocking our house last week on a raft foundation. we left it 2 months the longer you can leave it the better i think at least a month.

 

[ludermor]

Your engineer will be able to tell you straight away.
2 months is far too long, concrete has substantially cured after 28 days so you are just wasting time leaving it for 2 months. 2 weeks may be enough as the raft is supported off the ground itself and the pallets of blocks are spread across the slab to spread the load.

 

[Kateb]

Our blocklayers started three weeks after the raft was poured.

 

[jab1]

no chance i would let blocks be laid after a few weeks.

 

[ludermor]

Any scientific reason for this? Did you consult your engineer?