Waffle slab whether exposure before framing?

Hi everyone,

The builder I am intending to build our first home with is suggesting to leave the slab exposed for about a month before putting the house frame on. Builder's point is that leaving the slab longer without putting the weight, on allows it to settle down well. Doing that minimizes the risk of slab movement and then having minor cracks in the doors / window architraves .

As I am not experienced in the field, if you can share your professional advice and / or past experience would be highly appreciated.

Thank you
Cheers
Mixter.

sure concrete cures and becomes harder over a period of time around 7 days it will be 70%ish cured. Some builders like to wait a few weeks.

If you're building on reactive soils like clay, the more likely culprit of movement and cracks will be the slab moving when the clay expands and contracts due to weather conditions.

I would say your Builder has no idea as his reasoning defies engineering logic or more probable is that
he is having problems with materials supplies and trades?

Loading the slab with material weight compacts the soil and reduces differential settlement that causes cracking

Thanks Noname,

The soil test of the lot returned with Class H2 , highly reactive clay site. and it's been titled more than a year ago and the constructions won't be starting at least until October. So, I think, the ground may have enough time to adjust to new moisture regime.

So, after the slab has been poured, it should be no harm to leave it to settle for around a month before they start the framing.
Once the build is finished, the first think I am planning to do is to put around ground drain pipes to channel storm water to the drainage hole instead of allowing it to go under slab.

Got it!
so, when do you suggest to get the framing done after the slab has been poured?

youll need to put a path around the property with a minimum fall of 50mm/1M. If you want to go one further, add spoon drains to collect the runn off from the path and have that feed to silt pits> stormwater. We have provisioned for this.

Keep in mind the Bitumen Impregnated Tape they use to seperate the path frm the house has a strip that can be pulled off the top. Pull this off and seal the gap up with Sikaflex for extra protection.

Good
You'll need to keep a closer look/check on your build as these are trying and testing times (literally)
Keep an eye out for non compliance, bad workmanship, site pilfering, material substitutions, builders asking for more money, etc,etc
Remember to check all documentation include engineering, take photos, ask questions, get advise put everything in writing
and Goodluck
OT. I've put all my personal projects on hold for a short time ... the build climate is too HOT atm.

answered every question they didnt ask...

@ mixter - technically should be good a few days after. Though leaving it a month wont be detrimental either. I think BIM guy has a point around material /trades though and youre just being given a story to keep you comfortable. Its a very likley scenario.

Engineers design in capacity for success.. that's why we are trusted
OT, That's what I tell my kids ( 5th generation Engineers)
I find people tolerate rudeness, arrogance, etc from doctors and engineers when they provide data/proofs (social observation)
Cheers
Chris

Got it, I guess once the build is complete, I am planning to add concrete around the block about 1m or less width. So, I'll add the fall in that concrete and collect the water in the spoon drains and feed it to the silt pit provided by the Builder (I am asking them to put 4 across the house, 2 at front and 2 at the back and I can run the spoon drains towards either side when I am doing the concreting). Is that the way to do it? you reckon?

I will pull off the top part of the tape and add the Sikaflex to seal any gaps.

Thanks!

Thanks BIM guy, appreciate your comments. And that is why I am researching 3 different Independent Building Inspector to help me go through each stages of the build and also help me understand the HIA build contract when I get the contract to sign.

In terms of time frame, I don't think my project would kick off anytime before September and I am not in a hurry either.

Hey mixter move quickly to get your slab down delays and price increases beyond that becomes the Builders problem.
The builder is aware that the contract doesn't come into play until work starts on site and will come back at you with price increases, at worse continuing to push back your build. The Longer you wait the Bigger the price increase. LOL, I gather that wasn't explained to you by the new home sales consultant...Also get good contract advice homeone is your friend
Cheers
Chris

Um. That is a bit alarmist. Volume home building in Australia is predicated on fixed price contracts. 90% of banks and lenders won't accept anything else, and for good reason.

There are stipulations in some volume builder "fixed price" contracts around when price increases do occur due to many people signing house and land fixed price contracts where the land isn't expected to title for +12 months.

These increases are generally described as a flat % rate across the contract price and not related or tied to the price swings of commodities like timber or concrete. The prices are also often advised as locked in for 12-18 months and often advertised as such. The material cost differential expected is already factored into the base prices of volume built homes.

Volume builders increase those base prices periodically. Some have increased prices as often as 3x in the last 3 months recently due to material shortages/price factors. BUT if you've signed a fixed price contract, your pricing is set (generally speaking) regardless of if your slab is down or not.

The scenario you describe happens under very specific circumstance and doesn't represent the majority of residential scenarios.

Hey Guys,

yes, we paid the deposit to Dulger homes (they are not the volume builder) this week and now according to the deposit pricing, the base price is fixed for 12 months (meaning the additional upgrades prices may be changed). The base price is fixed given the below conditions.

1. Signing of HIA New Home Contract and payment of 5% deposit of the contract value within a period of 3 months from initial deposit
2. Provide unconditional finance approval within 7 months of initial deposit.
3. Provide proof of land ownership by way of land contract signature and proof of initial minimum 5% deposit on the land or proof of settlement.

If I don't fulfill the above requirements, Dulger homes reserves the right to apply an increase of 2% on the base sales price every 90 days.

Although I am going to email the sales guy to get more clarification on what the sales price for us is? and how much increase would it be if we delay for reasons other than in our control.

100%, Those that have money will sue the pants off the Builders in the Courts.
What do the Battlers do they struggle to raise the funds to Build their Homes.
those of use that have been around long enough have seen boom/bust cycles, but nothing like this. ie
fire, flood, plague , locked down borders, struggling governments , housing inflation, etc, etc
Best to know the worse case scenario and work from there.. an engineered trait
OT, "Get it from the Horses mouth (Builder)" to speak, as the salesman takes no part in the contract...
Please keep the members informed
Cheers
Chris

You don't need o understand the worst case scenario and work from there. You just need to understand the contractual terms.

All the scenarios are clearly set out in the contract. Take a look at mixters post above, it clearly highlights everything I've said to be correct. Now mixter is seeking further clarification around the actual figures. Short of that, the can have the contract reviewed by someone who understands the terms and can translate that into real dollar values for them independently. This will clearly articulate ALL scenarios to the consumer.

No suing, no rushing to get slab down, no drama. Just using your brain.

The bare minimum is set out in the contract, the rest is established by case law and the courts.
That is what is expected and provided in a contract that favours the Builder
Caveat emptor. lol, consumers buying a frypan have better protection that battlers building their dream home

I think you should stick to pouring concrete mate as i don't think you understand contract law as well as you might think.

I think you should stick to pouring concrete mate as i don't think you understand contract law as well as you might think.

I'm sure others will put their spin on this topic.
Here's a tip when you front court
They'll ask you to state you name, professional occupation and experience, etc.
Then they will dismiss you if you are irrelevant.