Building on Stumps. Cheaper, Better?
- Thread starter reeco
- Start date
From a layman's perspective (I am not a builder):
Building on a concrete slab pros:
* It is much cheaper (on a level site).
* Thermally, concrete slab houses are warmer.
Building on a concrete slab cons:
* You need pest (termite) barriers - physical or chemical, as you can't often see an attack point
* PITA to change plumbing / drainage (i.e. adding bathrooms) as it requires cutting the slab
On a steep sloping site, you'll need to cut & fill to get a level pad and also pier down in the fill part to get support before laying the slab.
Bearers and joists pros:
* Provide easy access to sub-floor
* Easy(er) to do termite inspections
* Can build on any slope
* Cooler in the tropics
* Easier to add extra rooms (possibly) or change rooms requiring plumbing/drainage around
Bearers and joists cons:
* More expensive - much more labour intensive.
* Levels have to be right - over time sinking/moving stumps may need
repacking
* Ant capping needs to be monitored for rusting through / needing replacement
Cheers, Alan
Building on a concrete slab pros:
* It is much cheaper (on a level site).
* Thermally, concrete slab houses are warmer.
Building on a concrete slab cons:
* You need pest (termite) barriers - physical or chemical, as you can't often see an attack point
* PITA to change plumbing / drainage (i.e. adding bathrooms) as it requires cutting the slab
On a steep sloping site, you'll need to cut & fill to get a level pad and also pier down in the fill part to get support before laying the slab.
Bearers and joists pros:
* Provide easy access to sub-floor
* Easy(er) to do termite inspections
* Can build on any slope
* Cooler in the tropics
* Easier to add extra rooms (possibly) or change rooms requiring plumbing/drainage around
Bearers and joists cons:
* More expensive - much more labour intensive.
* Levels have to be right - over time sinking/moving stumps may need
repacking
* Ant capping needs to be monitored for rusting through / needing replacement
Cheers, Alan
Natural compaction will win over a cut and fill, if you're worried about things moving.
With 2m drop you might be needing poles rather than stumps, otherwise you'd be looking at a split level house to avoid tall stumps. Split level for either style of foundation would have the minimal amount of weirdness happening but then the construction gets more expensive. You really need to know the amount of drop where you actually want to put the house, if for example you have a narrow house going across the slope rather than with it (if you know what I mean) you'll really minimise the amount of slope under the house.
I used to own a block of land with a steep slope and looked into this kind of stuff, but ended up not going ahead with a build.
With 2m drop you might be needing poles rather than stumps, otherwise you'd be looking at a split level house to avoid tall stumps. Split level for either style of foundation would have the minimal amount of weirdness happening but then the construction gets more expensive. You really need to know the amount of drop where you actually want to put the house, if for example you have a narrow house going across the slope rather than with it (if you know what I mean) you'll really minimise the amount of slope under the house.
I used to own a block of land with a steep slope and looked into this kind of stuff, but ended up not going ahead with a build.
Hi Reeco, I reccied one builder who builds on slopes, you can see their display house in Flagstaff Hill. Cost 30-40% more but you get split level, nice design.
Another one I saw in Torrens Pk was a kind of duplex with about 2m drop - they put criss-cross steel above the piles and the slab sat on the steel mesh. This created a biggish space under the house. They put all manner of stuff there, the plumbing, the water tanks etc It was like a decking.
I think the builders were Classic Homes, a fairly small & not very well known builder. My info may not be 100% accurate as it's from memory & a walk past look.
KY
Another one I saw in Torrens Pk was a kind of duplex with about 2m drop - they put criss-cross steel above the piles and the slab sat on the steel mesh. This created a biggish space under the house. They put all manner of stuff there, the plumbing, the water tanks etc It was like a decking.
I think the builders were Classic Homes, a fairly small & not very well known builder. My info may not be 100% accurate as it's from memory & a walk past look.
KY
Cheers guys,
Its only 2metres from the very front of the lot to the very back(140 metres). So if i build in a house that spans only 20metres of this then the angle would be only about ...umm ...Dang! i knew algebra would be usefull oneday!!! Let say a 30cm drop.
This sound too much/little for stumps/cuts? Slabs are fantastic to work off. Have been doing so for about 12 odd years myself. Ive just been advised(correctly or incorrectly) that stumps would be a great option
Its only 2metres from the very front of the lot to the very back(140 metres). So if i build in a house that spans only 20metres of this then the angle would be only about ...umm ...Dang! i knew algebra would be usefull oneday!!! Let say a 30cm drop.
This sound too much/little for stumps/cuts? Slabs are fantastic to work off. Have been doing so for about 12 odd years myself. Ive just been advised(correctly or incorrectly) that stumps would be a great option
I dunno reeco. Clay swells and contracts with moisture content.
Houses on stumps tend to handle movement much more easily than say brick houses on slabs (that crack).
Best to speak to a few builders with experience on your soil type IMO.
Thats what the suburbs im looking at are well known for. Alot of long running cracks in walls. Guess you could get around this by over-engineering the footings.
Will see what the local builders say. Cheers for that!
On a sloping clay site your biggest cost will be the siteworks and required engineering for the proposed load.
Those are the main reasons you switch from a concrete slab to a framed home. The savings can be $20-$40k in the hills.
Where are you thinking of building Reeco?
Those are the main reasons you switch from a concrete slab to a framed home. The savings can be $20-$40k in the hills.
Where are you thinking of building Reeco?
Gosnells and or Kenwick. Basically the gosnells district area. Been to a few house inspections and found a couple walls with cracks in them. Its funny i had a realestate agent tell me that its ok "coz all houses round here are like that" .His exact words... Nice salesman-ship on his behalf i reakon.
Forgot about them. Im sure one could convince a project builder to have a glance. It would make them more appealing to have a project on stumps under the belt.. Mind you thats probably a variation theyre not willing to accept.
There's plenty of timber frame on stumps project builders in SA that'll do quite nice designs for you, I'm sure other states have them too. You aren't limited to a 7m wide house.
We got misquoted with our house for having a slope (we don't) and they wanted to charge us an extra $800 for extra long stumps so its not expensive to cater for a smallish slope with stumps.
We got misquoted with our house for having a slope (we don't) and they wanted to charge us an extra $800 for extra long stumps so its not expensive to cater for a smallish slope with stumps.
How old were the houses? All houses get cracks over time simply due to shrinkage rates of different materials.
I've built a few homes in Kenwick and haven't had any issues. They've all been double brick on concrete too.
Sure, but there are cracks and then theres cracks that you feel a small breeze through.
1970+ im guessing these 4 i inspected. Wanaping Rd and along Kenwick rd. Some shockers. Usually houses on large lots that at some stage where/still are farming related.
Im guessing the engineering required for todays footings would be alot more expansive. Believe it or not ive found the shelves from a fridge!!! used as structural steel in concrete footings before!! I was in demo awhile back and it was a funny find.. I think these days 12mm reo is the lowest you can go.
The best 'crack' I've ever seen - back in 2000 - I could put my ARM through the entire wall, which was 40cm thick.
Unsurprisingly, that house was heavily discounted and they were having some 'issues' selling it. It was in an area you couldn't demolish.
Unsurprisingly, that house was heavily discounted and they were having some 'issues' selling it. It was in an area you couldn't demolish.
