Stumps or slab?

Hi all,

I have been asked by our architect if we want to go stumps or slab. The fall is roughly 1:15 from the road back down to the rear boundary. It is about 2.3m over 35m of build length, 45m long site.

The architect said she advises stumps due to the fall. She said it needs to be decided now before town planning submission due to elevations. A friend that is a builder who is developing the site next door said he is only going to decide when engineering drawings etc are drawn up i.e. after planning permit.

Around the area about 95% of build sites are doing slabs, even on sites with slopes more than ours. A builder I spoke with today said stumps are preferable on such a site but a lot of carpenters don't know how to build on stumps as stumps are done a lot less these days. I am confused.

Questions are:
1) Would you advise stumps or slab on such a site?
2) Does one cost more i.e. slab more concrete vs stumps more time and specialist?
3) Does one need to decide pre-town planning?

Thanks

 

This is complete BS.

If you are going to go with a slab on a sloping site, then you are going to have cut & fill. Then you will possibly need to pier down thru the fill and have retaining walls for the cut etc. My preference would be for stumps but that's just me.

 

I agree with @Propertunity - but what are you building? House? Barn? Man cave? Warehouse? Block of units?

Definitely go for bearers & joists for a house.

 

And find another builder.

 

Yeah, then you can eeasily also add things like heating ducts, more wiring, networking, storage...etc

 

Thanks everyone, it is a 4 unit development, 2 bed 2 bath single story with central driveway. It sounds like stumps are the way forward. It is just out of sync with what most are doing.

I have also spoken with several carpenters, they do very few developments with stumps these days (in Melbourne). Most are slabs so builder is correct. The site he was working on had a slope even worse than ours and they had gone slab for 3 units and stumps for 1. He was working off engineering drawings so had no choice in it. He said it was a big mistake for them to go slab for the 3 and was tough to do, they had to be poured in stages due to the slope etc.

All learning for me at this stage. I just don't want to make a choice so early on that I will regret for the rest of the project.

 

Many project builders now refuse to do anything but slabs. And many that offer a choice add a hefty charge for it. "Site costs" arent typically in the price for a project build and can be an expensive add on as can a engineered slab.

Slabs are far less effective for heating in Melbourne IMO. Underfloor ducting is better

 

Based on that description, you could do either or both. Your units will step down the gradient so there'll be minimal cut & fill or brickwork up to sub floor level. Your architect will need to guide the tender to experienced builders in the chosen methodology.

For a slight premium, have the engineer design both and get pricing on both alternatives.

What is the rest of the structure (brick veneer, cavity brick, reverse b/v etc)?

@MTR @Westminster @Leo2413 @BMT Tax Depreciation

 

Having seen @RickProp plans in another thread - adding below - I would expect that slabs could be quite easily accomodated with various small step downs.

Unfortunately there will be times when an alternative like stumps is the academic answer and in theory should cost less but there might be less trades doing it therefore prices go up and it becomes more economical to go back to retaining and slabs.

You could probably do 2-3 small terraces in the front to reduce the amount needed in the construction zone - lets say 1m in the front, 0.5m high retaining between u1/4 bed 2 and garage leaving 0.8 retaining along living/dining slab of u2/3

 

The builder is more confused as most wall frames are pre-fab and everything above the top plates is also..
As other's have said ,with the 2-3m fall you could step each down on interlinked slabs,and it would look totally different from being set on stump's ...imho..

 

Thanks everyone, does this need be decided prior to town planning i.e. now (due to elevations) or can we decide at engineering drawings stage, post town planning?

It seems slabs are certainly possible yet stumps are the theoretical solution. Practicality leaves us somewhere inbetween. I would rather leave the discussion to after town planning with an engineer if possible.

 

Thanks, what will give a better look in your opinion? I assume with stumps they are sitting higher or will the finished floor level be the same with both options? i.e. if we have decks will these be higher off the ground etc when coming out of lounges?

 

You just have to picture the end product ,in the right location then stumps may blend in,but with that fall range a slab cost wise may be the better option ..imho

 

We have a site with around a 2.5m slope, and we'll use 2 smaller slabs with the construction design custom engineered to fit and hug into the building envelope of the land to minimise cut and fill and retaining walls. We'll only have 1 retaining wall. The builder and engineering company worked very closely on it though in the design stage which helps alot if your able to do that.

 

DA stage does not require engineering design to be completed simply notation of footings (or slab or flooring to engineer's detail).

DA gets you the building envelope, bulk h general configuration and compliance with town planning matters.

 

where is this in melbourne?

 

What gave him away? (hint - there are no hills in Melbourne)

 

assumed from his title. no hills?

 

Currently building my Ppor. Strip footings with 200mm LVL's. No stumps. Much better than slab and all services are located below sub floor.

Not many builders have a clue building this way. Separates the boys from the men.

 

Is it massively over-capitalised & include all the whistles & bells?

(gotta love the use of timber )