To dig or not to dig!

Hi, I'm just after a little info. I have bought a new PPOR and downstairs is a 6 car garage that is 230cm high. I would like to build in rooms downstairs, so will have to find 100mm some how. The slab is good under the house and it's already on steel struts. Do I dig out the 100mm, or raise?

There is already an extension on the back (just 7 years old) which steps down the 100mm to be legal. It's got be stuffed shy they didn't raise the entire house then while it was easy to make it all legal.

So my question is, is it worth raising, or should I dig up the slab and relay one? What would it cost to dig approx 50 square meters and lay a new slab?

There wouldn't be a problem with drainage as it handled all this rain in Brisbane no worries.

Cheers.
 
on the quiet

If it's your PPOR and underground and you don't make any real structural changes... surely you can put up some plasterboard walls and not raise or lower then demolish back to current state if you ever sell.
 
Yeah I could for sure, but it's a big area, so it'd add plenty of value if we were to sell. I'l talking to extra bedrooms, large rumpus and bathroom/toilet. I will eventually add a kitchenette so effectively a granny flat.
 
If it's your PPOR and underground and you don't make any real structural changes... surely you can put up some plasterboard walls and not raise or lower then demolish back to current state if you ever sell.

If money is spent making it "habitable" then poidda would be wasting that money if he removed it all to sell. If he spends it, and leaves it as "store rooms" because it is not legal height, it will always be "tagged" as "not quite good enough" and the price will always reflect that.

There are houses around our area that I know of that are "not quite legal height" and they always seem to sell for less. People don't want to pay for "living rooms" that are not legal.

Perhaps this more a Queensland problem as there are so many queensland style houses that get built down and just miss the legal height.

We built under our place (dirt floor) rather than raise. We only needed the depth of the slab. It was legal height on the dirt. So we got in the machinery, including a rock breaker and it ended up costing us as much as if we had raised.

We are sitting on rock so the rock breaker was costing us an arm and a leg every minute. Had we known, we would have raised, but our back yard is straight off our kitchen/living area and very private due to its layout. Had we raised, we would have lose a fair bit of that privacy, so ultimately, it comes down to what else you gain or lose with the raising or digging down.
 
We were in the same position and dug out quite successfully. remember legal is 240mm to the LOWEST point so if you ned RSJs as wee did to take out many of the posts, you need to make sure you dig down that extra bit. Also remember floor coverings take away vital mms. We got our inspection done before we had timber floors laid as they were 8mm thick and it was a bit close.

We also had the issue that there was a partial slab laid and we couldn't find plans for how thick it was so they had to drill a bloody big core thought it to check and then fill it up again because - surprise surprise - it was fine
 
So you have already have a height >< of 2300mm and you require 2400mm ,

I would dig this out to a total floor to ceiling height of 2550, the reason for this height would allow you to have a 100mm 25mpa slab but also adding a 200um plastic membrane under and partially up the walls to reduce any further water issues that might arise further on , whilst you have the equipment there you may consider some new sewer lines and water pipes as well , ??

the reason for the height allow 100mm slab, and 30 mm for the metal batton and sheet and 10mm for the tiles ,
 
and if your going to go to all of this trouble you might as well spend another 4k and get it approved,

you might want to save the money now , but you will be kicking your self later if you dont go through with these approvals,
 
I reckon it depends on what is there. I you don't have external wall cladding then i would raise, you could then raise to higher than 2.4m. I think you would get more than your money back if you raised to 2.7 as opposed to 2.4m. I'm assuming you have 3m ceilings upstairs. Even if you just want to go the 2.4m and if you are on steel posts they can actually raise and cut the posts and weld in the extra bits. You then build the wall frames underneath out of 90x35mm at 450centres with double top and bottom plates (ie structural). That way your house is both sitting on the posts and the structural wall frames.

Raising from your height should be less than 5 grand, with steel extra if you need beams etc. The stumps, footings are normally the expensive part.

All of this depends if your slab underneath and your post footings are of sufficient size. Good luck
 
I reckon it depends on what is there. I you don't have external wall cladding then i would raise, you could then raise to higher than 2.4m. I think you would get more than your money back if you raised to 2.7 as opposed to 2.4m. I'm assuming you have 3m ceilings upstairs. Even if you just want to go the 2.4m and if you are on steel posts they can actually raise and cut the posts and weld in the extra bits. You then build the wall frames underneath out of 90x35mm at 450centres with double top and bottom plates (ie structural). That way your house is both sitting on the posts and the structural wall frames.

Raising from your height should be less than 5 grand, with steel extra if you need beams etc. The stumps, footings are normally the expensive part.

All of this depends if your slab underneath and your post footings are of sufficient size. Good luck

Thanks heaps for all the info. I am leaning towards raising rather than digging out. If I can get rid of a couple of posts while I'm at it by using some steel beams that would be a bonus to open some of it up a but more.

Most of the external walls are just fibro at the moment, so that's easy. There is an extension on the back. I'm thinking if I can get away with 10-15k for the lot it would had plenty of value.
 
I'm thinking if I can get away with 10-15k for the lot it would had plenty of value.

That figure sounds a bit low. Don't forget to allow for a slab, electrics, plumbing and sewer extensions to meet the new height.

The first time we raised, the quotes were quite low, until a realistic chap visited us and told us all the "add ons" that the other quotes didn't include.

Also make sure your house is insured if it falls. My belief is that many will say "we are insured" but you want to ensure that YOUR HOUSE is insured, not just the house raiser and his workers.
 
Thanks heaps for all the info. I am leaning towards raising rather than digging out. If I can get rid of a couple of posts while I'm at it by using some steel beams that would be a bonus to open some of it up a but more.

Most of the external walls are just fibro at the moment, so that's easy. There is an extension on the back. I'm thinking if I can get away with 10-15k for the lot it would had plenty of value.
I don't think you would do it for that price,once you take the materials cost factor,plus the plumbing-gas-elecs,council permits,plans,then if the back section is already set there may be problems,first of all ring up the BCC,and have a talk too them,a very easy way is do a takeoff on all the materials,plus labour costs,just the permits for the plumbing will be above $700.00 to start with,but check with the BCC first and find out if everything is legal with the back section..good luck willair..
 
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