Building on sand (Fern Bay)

[Aaron Sice]

maybe due to the water table?

footing here in WA for a single storey house are 250 deep and 350 wide with no mesh infill - std 20MPA conc. some shire stipulate trench mesh F62 - but places like swan etc? no mesh.

slabs are 100mm with F62 mesh.

try that in clay.

 

[battler]

try that in clay.

Yes I understand, we've just done a slab with beams 350 by 450 deep with F12 trench mesh with F82 mesh, including stiffening beams, and its got a hairline crack already

What I was curious about in Fern Bay was, why they had to put it on piers if sand is so stable.

Thanks.

 

[Aaron Sice]

water table too high? shire conditions? dunno....

 

[craigb]

Yes I understand, we've just done a slab with beams 350 by 450 deep with F12 trench mesh with F82 mesh, including stiffening beams, and its got a hairline crack already

What I was curious about in Fern Bay was, why they had to put it on piers if sand is so stable.

Thanks.

The piers are used to stop the house sliding, some slip accross or side ways etc.. just a little 3mm or so, and on the other note, ALL concrete cracks, thats why the mesh is in it ?

 

[vbplease]

footing here in WA for a single storey house are 250 deep and 350 wide with no mesh infill - std 20MPA conc. some shire stipulate trench mesh F62 - .but places like swan etc? no mesh

slabs are 100mm with F62 mesh.

try that in clay.

BC, I’m curios why the BCA isn't designed to WA? Based on AS2870 Residential slabs and footings, minimum beam dims for a raft slab are 300 deep regardless of soil conditions. Slab thickness of 100mm is standard.. regardless of soil conditions. Also interesting to note that the same beam dims are used for "slightly reactive clay" here in Brisbane as your sand in WA

And unreinforcing a slab shouldn’t be an option.

Yes I understand, we've just done a slab with beams 350 by 450 deep with F12 trench mesh with F82 mesh, including stiffening beams, and its got a hairline crack already

Battler, just my opinion, and without knowing much about your raft slab and the conditions, I doubt the hairline crack is from the clay’s reactivity.. Not sure about Melb, but it didn’t rain all last month up here, and it hasn’t been hot enough to lower the moisture content? It’s the nature of concrete to crack.. all concrete shrinks (it’s inevitable), and possibly temperature contraction (quite possible in Melb). Its just the extent of cracking which is controlled by reinf mesh, and control joints i.e. limiting the slab length.

 

[battler]

Thanks, and yes it wont be due to clay movement this early, and i'm not concerned about it.....I just have to get the carpet down quick so I don't have to explain to the Mrs!!

 

[jimbo_jones]

Why did you have to pier to this depth?

The majority of the slab area (some 350sqm) was just waffle pod on compacted bedding, but there were sections which were on fill and piers were required. Apologies for not proof reading previous post...it was typed in haste.

 

[Aaron Sice]

BC, I’m curios why the BCA isn't designed to WA? Based on AS2870 Residential slabs and footings, minimum beam dims for a raft slab are 300 deep regardless of soil conditions. Slab thickness of 100mm is standard.. regardless of soil conditions. Also interesting to note that the same beam dims are used for "slightly reactive clay" here in Brisbane as your sand in WA

an engineer can operate outside the BCA if deemed to satisfy.

builders here have been doing it for 10 years - at least.

my house has whopper footings - 400mm deep and 400mm wide.

 

[Panadawn]

Old thread, I know. Found it on Google.

Just FYI, the sales brochures at the Fern Bay development state the soil there is "Class A: Most sand and rock types, little or no movement from moisture changes."

 

[Aaron Sice]

sand is class A - yes.

 

[Snort]

Blue Card you must be talking about a lot of the upmarket builders in Perth. Most single storey builders only use 85mm concrete slabs

And yes Sand is an excellent base.

Concrete piles should only be required for high water tables or evidence of other matter such as peat.

Hairline cracks happen in all concrete applications, they aren't structural.

I can point to atleast 20 things where most WA home construction isn't inline with the BCA... but blue card is correct again that the Engineers detail is deemed to satisfy the performance requirements of the BCA therefore OK to construct.

 

[HomeBuyAU]

I would be very careful about buying a home on sand!.

In saying that, Fern Bay is getting good returns and I wouldn't mind knowing if all properties there are built on sand or is it just this new development?

 

[bespoke]

Drive past it every day

I live about 30 mins North of Newcastle and drive past the new estate at Fern Bay every day.

The blocks have had a significant drop in price since they came on the market (about the time everyone stopped buying). In my opinion they were massively over priced to start with.

My hubbie and I looked there when the blocks were first released,I think about 2ish years ago, they have some interesting covenants on the land, only allowed certain colours and not allowed to have a curved roof??????????? WTF?

Anyway, no where near schools, no where near any major shopping centre, the closest super market would be a small indepedant in Stockton maybe 5 k away. Its a bit of a satelite suburb at the moment and although geographically close to the CBD of Newcastle, you have about a 20 min drive to town. Definatlely need a car if you live there. Handy to the airport though.

Right next door (although a bit of bush separating it) to a mobile home village.

Have to say, I think their advertising is extremely deceptive as they show people on the beach, in reality it is seperated from the beach by alot of natural bush land (that I think is reserve) and the only way to get to the beach is to walk or you have to have a 4WD.

Close to a new upmarket retirement village but that village seems to be taking a long time to sell their ridiculously expensive homes.

There is a really nice landscaped park there with paths for the kiddies to ride their scooters etc.


I bought 3/4 of an acre 10 mins up the road in a upmarket estate with kerb and guttering and all services in the height of the boom (doh!) for cheaper than the original asking prices for the Fern Bay blocks.

There is alot of land North of Newcastle (between Stockton and the airport) and the possibility of future development. I think the land is owned by the local aboriginal land council, depends what they want to do I suppose.

 

[gg1965]

My initial thought of Fern Bay is that it may get a few DHA homes in there (being close to the Air base), but lack of schools, shopping facilities and services in general may be problem as the homes there may not meet the DHA requirements (for the reasons i mentioned above).

It does seem a long way to any decent shopping facilities But one thing that Fern Bay does have going for it is it's proximity to Newcastle Golf Club (even though i love golf, i don't think that is a good enough feature for Fern Bay).

I also questioned how close it is to the beach and i was told by the agent that it is a quick 5 minute walk. You'd have to be walking VERY quickly to make it in 5 minutes. He was obviously having a lend of me by saying that.

But between Nelson Bay and Newcastle (Stockton) there is a lot of land and a lot of opportunity. Some of the land is swamp though (which didn't stop them when they built at the back of Wallsend) but i would much prefer to be in the Newcastle CBD, inner city area.

FWIW - I still love Stockton and i still think it is a forgotten, or hidden secret. The only thing that is stopping me from buying in there is the threat of rising sea levels and the already happening diminishing Stockton Beach.


G

 

[bespoke]

Further to my previous post about Fern Bay, another one of the covenants was you are only allowed to plant certain plants that are on their approved list..................
Don't know how they will police that in 10 years time, maybe a vigilante residents group with horticulture courses under their belts.

 

[bespoke]

Yes, I think that that land is the next natural expansion of Newcastle, although I'm pretty sure it is in the Port Stephens council area so would be subject to their development plans.

Could be a very nice area in 10 years if the development continues, close to the beach albeit a bit of a walk and currently a long way from any patrolled areas of the beach. And as for the swampy areas, there is alot of land back towards Newcastle on Nelson Bay road, about 100 metres from the entrance to the Fern Bay estate that has had about 1 metre of fill put over several acres about 2 years ago. my father tells me there was fill put in the same place a few years back as well. probably about 1.5 metres all up I reckon. Not sure what is planned for that spot, I would love to know. May pay to find out as it may impact on your decision to buy there.

So I don't think a bit of swampy ground would stop any development.

I live in a street where about half are DHA houses and the house next door (not DHA) was up for sale about 3 months ago and DHA looked into buying it. Our ex neighbours said they told her they have a chronic shortage of suitable DHA homes in the area and they must have been desperate to even consider this place as (although only 4 years old) it would have needed new carpets, a full internal paint job, security screens for windows. landscaping, garden shed etc etc to come up to DHA standards. This is about 10 min drive from Fern Bay, just a bit of local inside info.

Didn't know DHA required close proximity to schools shops etc!

 

[Aaron Sice]

so funny - folk that wouldn't build on sand - would hate to see you live in Dubai or WA or Singapore or the USA....

 

[pudestcon]

Blue Card you must be talking about a lot of the upmarket builders in Perth. Most single storey builders only use 85mm concrete slabs

And yes Sand is an excellent base.

Concrete piles should only be required for high water tables or evidence of other matter such as peat.

Hairline cracks happen in all concrete applications, they aren't structural.

I can point to atleast 20 things where most WA home construction isn't inline with the BCA... but blue card is correct again that the Engineers detail is deemed to satisfy the performance requirements of the BCA therefore OK to construct.

Had a meeting a couple of months ago with Structerre engineers who were flogging the concept of 75mm ground floor slabs using fibre instead of steel reo. We researched the idea with concrete suppliers etc and decided against the idea.

 

[gg1965]

so funny - folk that wouldn't build on sand - would hate to see you live in Dubai or WA or Singapore or the USA....

Well Dubai - too hot
WA - too far from anywhere
Singapore - too expensive and too small (but little India is good)
USA - well it is the USA.

NAH wouldn't want any to live in any of the above.

 

[Aaron Sice]

Had a meeting a couple of months ago with Structerre engineers who were flogging the concept of 75mm ground floor slabs using fibre instead of steel reo. We researched the idea with concrete suppliers etc and decided against the idea.

most builders i use, use 100mm slabs because the engineer certification for 85mm slabs costs more $$ and time than just laying the 100mm slabs in the first place.

and there's no surprise engineer's a pushing for 75mm slabs - they have to sign off on each one laid!!!!