How long should I wait before building a shed on a new concrete slab?

[mathans86]

Hello,

I just had a concrete slab laid in preparation for installing a 4.5m x 1.5m Build-a-Shed that I purchased from Bunnings. What is the suggested number of days to wait (from the concrete pour date) before I should construct the shed (i.e. drilling holes in concretes for the shed bolts)? I have read various timeframes on several forums. The most common advice is to wait roughly one week, that would be sufficient. Although not 100% cured, it is sufficient enough for the purpose of installing the shed. 

Any further advice would be appreciated. 

[EricL]

Hello @mathans86 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your concrete slab.

Weather conditions play a big part in your slabs curing time. Although cement is a chemically activated product, it does require several days of good sun to completely dry it out. If drilled in too soon the face and bottom part of the slab could splinter and cause microfractures to occur.

I suggest doing a slab test and placing an A4 sized plastic piece or bigger over the surface of the slab. Tape the edges if possible and cover the edges with brick or timber to prevent it from flying away. If condensation forms under the plastic within several hours, it's an indicator that it is still curing. 

For a measure of safety, I suggest giving it an extra week for curing, especially if there has been no sun in the past week. 

Let me call on our experienced members @Peggers and @diy_hausdesigns for their recommendations.

If you have any other questions we can help with, please let us know.

Eric

[mathans86]

Thanks for the quick reply, Eric. 

So you recommend I wait until until the slab is 100% cured?

To confirm, I should do the slab test, and once no condensation forms, I then wait another week before drilling into the slab? 

[EricL]

Hello @mathans86 

It would be for the best, a few extra days letting the slab cure will be to your advantage. A fully cured slab means that you can drill into it without having to worry about damaging it.

If you need further assistance, please let me know.

Eric