Drainage Footings and Slabs

Wet Weather Spells Building Trouble

It’s a wet day and maybe a wet weekend in Brisbane.  Is your builder pushing ahead with your new house? You might need us soon!

Rain causes problems for builders
Rainy weather can be bad news for home builders

Keep these ‘watery’ facts in mind:

  1. Adding water (even rainwater) to wet concrete makes it weaker and more likely to crack as it cures.
  2. Water IS required to help your concrete cure. Rainy weather is perfect for this.
  3. Adding water to clayey ground makes it swell and lift. If your slab is poured after lots of rain, when the ground dries out you could be left with what looks like subsidence
  4. Poor drainage around an unfinished house can have long term consequences. Get your builder to make sure your site is free-draining.
  5. If your builder refuses to improve your site drainage during construction, take photos of water ponding near your house to help with insurance claims later on.
  6. Water softens the ground and makes it impossible to achieve the solid ground surface you need under waffle slabs.
  7. Rain water on timber flooring usually isn’t a problem. Contact your builder or supplier if you have any questions.

2 replies on “Wet Weather Spells Building Trouble”

Ive been told to set up a sprinkler to help a finished raft slab cure (800mm deep footings). But then that means a lot of water on site. So should you water cure a slab or not?

Hi Claire
I may have been a bit slow for you – but a sprinkler system to help cure a new slab is an option – it just isn’t the easiest option.
Yes, you will need to ensure that wherever the water from the sprinkler drains off the slab that it can drain away from the building with no impediments.
The alternatives are laying plastic over the slab, spray-on curing compound and damming the slab and flooding it. it will depend on your floor finishes, the weather, the availability of plastic and curing compound and/or sand for bunding the perimeter.
Does this help? Albeit maybe too late?
Matt Cornell

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