Tilt up

[dook]

Hi everyone,
In my area (southwest west. australia) their are a lot of tilt up commercial buildings (buildings made of concrete panels formed on the ground and stood up as wall panels).
I have often thought that its only a matter of time until this form of building is incorporated in the housing sector. I see that some builders have had a shot at it in appartment type developments and the occasional house, but i havent seen any real push for housing.
Now i.m.o. this could be that many large builders are making their own products, bricks etc. and like to keep it that way.
Anyway i guess my question is can anybody see a trend toward this type of building creeping into the housing sector in their area yet, or is it only viable for larger buildings , warehouses and the like.

Any comments or thoughts appreciated.

"Dook"

 

[Kevmeister]

In Cranbourne where I used to live, some of the houses were commission houses and were prefabricated concrete slab panels. They were always built on concrete slabs. I don't know how the insides were finished, but I believe this is an important issue. They were very similar, if not identical, in appearance. You could probably count 100 or more of them in this particular estate, peppered amongst the brick houses.

My opinion is that this form of construction offers advantages in some areas with disadvantages in others.

I could talk about heaps of construction issues associated with this type of construction, often simple things taken for granted like attaching skirting boards with nails are not so simple when the substrate is concrete. How quickly can you attach a skirting board if you need to rotary hammer drill holes every 600 mm or so along the wall? Not nearly as quick as someone with a nail gun... This is also my guess why steel-framed houses have never taken off - they still make supposedly simple construction issues more difficult.

Of course, there is the possibility of using concrete panels purely for "cladding" to replace brick but the question would be "why bother". You would need a crane to lift them into place, which probably negates any cost saved by not needing a bricklayer. You would have to be building a lot of the same style of house simultaneously to make this cost effective I would think. Exposed concrete would largely be unacceptable for the outside surface of a house, so the bare concrete surface still needs to be finished off.

Physically there are different metrics to consider between houses and factories. Consider the wall area to door/window area of a house compared to a factory - the factory will need very few "special shape" panels because most of its walls will usually be solid and full height. Houses have lots more openings on nearly every wall, so nearly every panel might need to be custom in some regard. I would expect this would make the panels *expensive* to produce.

For ordinary houses, if construction time was important then rendered Blueboard (fibre cement) might be quicker - goes on in sheets; uses standard timber framing (or steel I guess); doesn't require heavy lifting equipment etc.

But the fact is that if tilt-panel or pre-cast panel concrete was substantially cheaper I think a lot of builders would be using it, and they are not. In the cases where it is being used, I think it is either specifically because the owner requested it (I seen one such property being constructed on one of the property shows about 12 months ago), or the building demands that style of construction anyway (ie. multi-storey or high-rise apartments etc).

Same argument goes for double-brick residential construction (although that is still popular in WA, but not so nearly everywhere else).

My 2 cents worth.

 

[JoannaK]

these days in the high rise building industry bricks and mortar are being replaced with Hebel and another form of concrete casting, the name of which escapes me at the moment. Bricks and mortar are the support structure of the building.

Hebel is basically aerated concrete, which is lifted in place and secured by a special adhesive. In this type of construction the concrete slab floors maintain the structural integrity and support of the building and the hebel is merely a skin around that structure.

The other is similar to concrete panelling, but it is hollow. It is lifted in place, secured, then filled with concrete to strengthen it. Again, this product sits on the concrete slab, so is more of a skin than anything structural or supporting.

The advantages: quicker, no stuffing around with bricklayers and suppliers....they are notoriously difficult on sites. And because they are not load bearing, they withstand ground movements much better than bricks and mortar.

The disadvantages: expensive as craning costs escalate very quickly.

I've seen factories built from concrete tilt panels many times. It is also very quick and easy to do. You need to make sure you've got a very good engineer to oversee the process.

One particular developer I know of in the Sutherland Shire built some factories using this method and his engineer had experience with tilt panels, but not on large projects and totally stuffed the job! The had panels too short short, too long, and many had to be redone.

I've only ever seen it done to a house once on one of those property shows on TV.

 

[Sim]

The Meriton high rises recently built in St. Leonards (Herbert St) - seem to have been made from pre-fabricated concrete slabs for walls. They went up very very quickly, and look very ordinary.

Haven't seen this technique in lowset housing - but then I haven't looked. Some of the more modern style kit homes with a rendered finish - surely it would be easier for them to be pre-fabricated, especially since they make lots of the same house ?

 

[Cathy B]

There is a builder in the Taree NSW area doing this type of residential building and I know of a house near here constructed using this method however it is set below ground level and the roof has lawn on it. Apparently it was extremely cheap to build.

Councils in colder climates such as here now want the panels to incorporate insulation such as polystyrene to help keep down wood smoke emissions. Making it more difficult and therefore expensive to manufacture.

Cathy

 

[Cathy B]

see http://www.energysmarthomes.com.au for Taree builder.

 

[Glenn]

Please forgive my ignorance if this is a silly question, but....do concrete sided properties still have a cavity wall system? Or does concrete not need it???

Glenn

 

[dook]

Thanks for the feedback i appreciate it.
I think it could be a cheaper way of building if the builder / owner builder knew concrete and formwork . And a well thought out plan of attack, knoweldge of crane and dogging etc.
I have been arround this sort of construction for a long time and we often say its a wonder no one is doing this in housing. Sometimes the inside is stud walls sometimes it is just concrete with a painted surface. Their was some talk years ago about the moisture seeping through the concrete (called capilary action) maybe the exterior coatings are better now for tilt ups. Council approval in diffrent areas would have a lot to do with acceptance i suppose.
With a smooth opperator and a good architecht i think this type of construction is an option although a careless builder can really stuff it up as precise dimensions and organisation are a huge factor and you dont see to many builders with those qualitys any more.
Thanks for the link Kath ( now in my opinion that is doing it the hard way, the scaffolding and formwork would cost as much as the house
Thats the sort of engineers we have over here too (w.a.) Jhoannak (oh! oh!)
Yes Sim a lot do look ordinary, it needs a bit of immagination to break up the structure wich can be very bland.
What you say i agree with Kevin diffrent methods diffrent problems but i dont think tilt up has reached its full potential in housing, we,ll see.
Generally Glenn concrete dosent need a cavity although as i said 'diffrent councils........and diffrent uses.' if a stud wall was required a furring channel set up like the ceiling would be quicker i think , maybe they do this?
This has been a question that has been debated more than once at smoko, so nice to get some info from arround oz .
Thanks again for the feedback.

(Dook)

 

[Joe D]

As a West Aussie with some engineering experience, I don’t see tilt slab taking off for domestic low rise construction. Tilt Slab as I see it, lends itself as an offsite construction method for multi-dwelling or multi-storey construction. Cranage, engineering and the need for multi-construction to make this economical, also make it subject to union orientated sites which in itself is a separate issue. Low rise construction (less than 6 units) whilst labour intensive is less restrictive and better suited to the smaller developer.

PS: I’m sure tilt slab construction has its economies, but with recent industrial incidents, plus union involvement, the HSE issues make this even less attractive for the smaller projects.

Just my tuppence worth.

Joe D

 

[brains]

I think there might be issues with regulations here, as far as i know residential building codes need an external and internal wall
for houses. (ie: cavity)

Also with no cavity, there is nowhere to conceal services.

eg:
plumbing, electrical/coms cabling...etc...in a commercial building it doesnt matter but people dont want exposed surface conduit/duct/pipes on their dining room or bedroom walls and to chase them in the tilt wall would negate any cost benefit .

This type of building will never be used for res. houses, if it was viable (or allowable), builders would be onto it big time by now.

ps: Brickies are no different to any building trades, give them fair conditions, good money and treat them well and you'll get a happy tradesman and a great job. (from someone who spent years as a subbie doing cottage work)