Building in Under

[Kenchiku]

Hi All,
There are so many experienced people here. I'm a novice but I like the idea of doing it Myself.

I'm thinking to raise my Queenslander on Steel RHS, then build a timber floor, External + Internal walls and a staircase. I guess that a timber floor is easier then a concrete slab. I'm also thinking of using recycled materials from demolished houses.
Does anyone have stories from their experience of doing this.

Thanks..

[Jacksin]

G'day Kenchiku. I saw a home reno program on TV a fair while back where a guy raises this style of house on his own. Living in SA it is all foreign to me, but it looks like one hell of a job.

As the show went on the owners, who were trying to most of it themselves (once the house was up in the air) struck one problem after another and the costs escalated by thousands $$. Problems with sewer lines, house being unliveable for weeks, the bobcat moved in to excavate they struck rock and so on. From memory they built the lower floor on a slab floor and brick walls. I think if they had their time over they would have second thoughts.

Others here might point you in the right direction.
Good Luck
Jack ;)

[Kenchiku]

Yes, I remember that one....It did look a bit out of control. Even though I won't need to excavate I do see what you mean about unforseen things. I will be lifting so I will need to move out while water is disconnected. I know there are many more....

Thanks
Ken...

[tcns]

I am very interested in this thread I want to do the same,

I am trying to find out what sized RSJ I will need and how I work out the spans.
I assume I will have to employ the services of a structural engineer.

I have worked through a plan on the actual lifting and I have access to earthmoving equipment that I can use myself I am very interested in peoples
thoughts.

Tom

[numbat]

I am trying to find out what sized RSJ I will need and how I work out the spans.
I assume I will have to employ the services of a structural engineer.

Tom
You can be absolutely certain that the council or whoever is in charge of building will want to see an engineer to specify the the size of the RSJ, and the structure that holds it in place as well as the footing that supports the structure.

If you are planning something like this you will need:

1. planning approval for what you are proposing - will need drawings to show what is proposed (in general terms) - may need to consult neighbours etc. This is a detailed concept approval.

2. once you have the above - you will need the engineers certificate and design showing the detail design

3. generally an independent certifier to certify the work is done as per 2 above

Cheers

[tcns]

Thanks numbat,

My thought process is not nearly as disorganised as that last post of mine is.

I am having and architect draw what we are after as a concept and then either he or I will put it to a structural engineer to get the details of the supports and a diagram/report on what is required for foundation and supports.

From there I will most likely order steel, and get it in place under the house on the current stumps, lift and secure and then put in the new stumps and set them as per the engineer's advice. I guess then excuvate the earth under the house, form up underneath (another visit from the engineer) pour the slab and they we are half way there :)

Things I can think of from here.

1. electricity - does it have to be switched off - is it just the possibility of pulling the earth out ?

2. Sewer - to be honest my sewer main needs replacing due to tree roots and age so that can be dug in before hand.

3. storm water - don't have one at the moment may as well dig one in to the gutter

4. Water main, have to get it switched off I suppose and re-done.

5 .I have seen posts made with threaded ends for self leveling - I would specify those so I can even the house back up

6. Cracked plasterboard, I guess patch and repair.

Head hight, I need to maintain an 10" ceiling downstairs plus room to accommodate the rsj, and ceiling frame, water/serwer services from upstairs.

Any other thoughts?

Tom

[Theremin]

We have recently done this little exercise. Here's some things to think about:

- What value will lifting and building under add to the property? What rooms can you add, and will you get better views? Is the value added more than the cost of doing it? As a rough guide, allow $100k unless you can do a lot yourself.

- Make sure your builder has insurance or you are covered by the BSA!!! House lifting can go wrong and, if it does, chances are you won't have a house any more.

- Consider whether the house should be moved to a different place on the block. If there is a better position for it, now is the time to move it.

- How high you are lifting won't affect the cost much. So if it is a Queenslander, think about going a bit over the legal minimum to keep the feeling of high-ceilings throughout the house.

- Electricty mains should be disconnected from the electricity pole. Although if it is only a small lift they might not worry.

- EVERYTHING will be cut when they lift the house... downpipes, sewerage, electrical, phone, Foxtel, gas, water. Do some of this yourself in advance, if you can, otherwise the house-lifters will disconnect everything using a 9" angle grinder. Don't forget to allow for re-connection costs. Also, check whether your electricity meter box has to be relocated.

- Lifting is pretty quick - maybe takes a day or two. Then the new posts and steel beams go in. Obviously you need to have the plans for downstairs done at this stage so you know where the posts will go. We used PFC230 beams which I think are good for a span of 5m, and 75x4 RHS posts. A structural engineer will be required. If you have brickwork/blockword around the perimeter, it will need to be extended up. Then the house gets lowered back down onto the new posts, and things can be reconnected. All up, it took us about 6 weeks until we could move back in. The slab downstairs was done after that.

- All doors/windows will need to be open for lifting. So, if you have any windows that have kind of stuck over time, free them up. Also all pictures, paintings, mirrors etc have to be taken down. If you have any delicate furniture, high shelving etc either remove it or make sure it can't fall over. We only had one shelf fall down... unfortunately it fell on my stereo :mad:

- How will you get into your house once it is lifted? We used an extension ladder for 4 weeks while we waited for the carpenter to build new front steps. Not easy getting the groceries up an extension ladder. Don't forget the cost of the steps, too!

- If you have VJ walls, these will move around a bit so invest in a stockpile of No-More-Gaps. I presume plaster would need some patching too. Most likely some doors/windows will need planing to close properly again.

I'm sure there's more, but there's a few things off the top of my head. Let me know if you have any specific queries.

Just to whet your appetite, I have attached a pic of our place up in the air.

[tcns]

Hi Theremin,

Thanks a lot for your post that is great insight,

Do you have any more photos of underneath during the lifting process
and who did you use ? Can you give me round figures of how much the lift
alone was ?

I would be doing this job in a similar way to yours.

Lift, slab, build under.

Like I said, I am just keen to see the process and support structure, I have consulted engineers with this, I want to excuate under my house first myself and still have it stilling up there and then look at a lift from there.


Thanks for your help
Tom

[bitingmidge]

All those thinking of lifting themselves.... don't !!

The risks are too great, and getting the re-stumpers in is relatively cheap. They have all the right gear, and the bozos who don't seem to mind if houses fall on them!

You won't have insurance if you do it yourself under any circumstances, and unless you are really big and strong, carrying all those big heavy styes will wear you out!!

If you live in Bris and want an engineer who knows a bit about this stuff, send me a PM and I'll give you some details.

As for lifting it higher than the limit... yes you'll get the feeling of high ceilings when you are inside the house, but you'll completely bugger the character of it from the outside. Have a careful look at a Queenslander next time you drive past, and you'll note that the proportions invariably give barely standing height under the floor.

Whatever the reason for this historically, it is one of the things that actually gives the well known character.

Cheers,

P (Who in one life designed hundreds of renovations for owners of Qldrs, and spent a lot of time finding innovative ways of retaining the proportions, none of which allowed high ceilings on the lower level!)
:cool:

[Kenchiku]

Hi Theremin,

Yes, that's a great list. Yes, who did you use for the lifting and how much was it if you don't mind me asking. I gues you have the cost of 1. The Steel, 2. The lift itself, 3. The reconnections and 4.The slab.

How far are you through your project?

Thanks
Ken

[journeyman Mick]

Ken
I wouldn't consider doing a lift myself, and I'm in the building game. I doubt very much you would be saving anything on the lift process by the time you factor in the cost of hiring/procuring all the lifting gear and timber for styes. The blokes that I've seen used a bobcat to lift all the styes into place. You will also be paying full price for all your steel and concrete and if you need a pump to place the concrete you may find that you won't get one unless you have someone in the trade organising it, as they're usually flat out and not interested in working for owner builders. You will need to get insurance cover for the entire job as well because your household insurance won't cover you. Then how good is your welding? Can you produce welds to meet the standards? Do you know what to look for in a weld?

If you want to do some of it yourself I would suggest doing all the prepwork, organising plumber to cut all the copper and replace with a few big loops of soft drawn copper so that you'll have the water back on straight after the lift, getting a sparky in to do the same for the wiring and telephone. Then get the pros in to do the lift and new beams/posts whatever. then if you really want you can do the new stuff underneath. Unless you have a mini excavator and lots of practice pay someone (with insurance) to do it. If you can place and finish concrete so that it's level, smooth and free of voids then pour the slab yourself.

Building isn't rocket science, but there's a hell of a lot more involved than the home reno shows would have you think and lifting a house, excavating underneath and building another story under with disconection and reconnection of services and provision of new services is more complex than building a new house. Would you feel confident building a house from scratch? If not, then lifting your house would be a nightmare. Sorry to be so negative, but I really don't think this is a job that a novice should consider.

Mick

[Sturdee]

Sorry to be so negative, but I really don't think this is a job that a novice should consider.


As usual you're right Mick. Even in the TV reno show they used professionals to do the house lift and they still had enormous problems and cost overruns.


Peter.

[tcns]

Had the architect over last night for a look around.

He had some really great advice, basically the fall of my to the street is such that I could remove all the earth I wanted underneath and make it the right height. It would be about 450mm + slab which would be a lot of dirt to remove
to but entirely possible

He is providing me with the specifications of the steel etc.

I am kicking off on the weekend with the digging, love the mini digger I have got at the moment. I will take some photos and start a new thread on the work

Thanks for you input and sorry to hijack the thread

Tom

[capedcrusader]

Hello Kenchiku/Tcns/Theremin et al
With due respect to the cautionary posts Im planning on doing this as well.
Theremin - from your photo it seems that the house was supported on 2 temporary UBs - any idea why the house lifters didnt place the actual final steelwork and use that to lift the structure??? I saw a house being raised recently that was quite big and was supported (under supported) on four stacks of hardwood and 2 UBs and the UBs were bending under the strain - cant imagine how much repair/make good work would have been necessary as a result.
I was planning on sliding the steel under, raising and fixing it to the underside of the current bearers and jacking that to the required height with 10 tonne hydraulic jacks (about 60 bucks each) in small increments - although Im only going to be raising mine about 1 metre if its OK with the friendly fascists down at town planning. I dont have a problem with preserving proportions because the level of my block is about 2 metres above the road and the house is practically on its guts anyway. When its at the correct height I plan get earth movers to excavate the appropriate places for columns (sort of hard to explain) then bolt fix the columns then excavate the rest for a garage. I got a quote to excavate 60m2 of dirt for about 4 grand and it will take about 2 days - how easy is that?? Kenchiku - Id be interested to hear about your plan for the actual process of raising your place. Id also suggest that you use the trading post for sourcing timber rather than recycling yards - the ones that Ive seen are either a bit crap or are extortionists - one guy was selling 5 3/4 Hoop flooring for $11.00 bucks a metre when you can get it machined from new dried Hoop for about $3.50. I recently bought two 8.5 metre lengths of 100 year old ironbark for $3.50 per metre (straighter than a skinhead on Hitlers birthday) from a trading post source. (bridge wrecker) And didnt it look dodgy strapped to the trusty F100!! Drove passed a motorcycle cop but thankfully he chose to ignore it - too much paperwork I suppose.
Here's to ya.

[Theremin]

Theremin - from your photo it seems that the house was supported on 2 temporary UBs - any idea why the house lifters didnt place the actual final steelwork and use that to lift the structure???
Not sure. They lift houses for a living so I assume they knew what they were doing..

[Harry72]

I cant understand why raise then build in underneath... why not add another story on top wouldnt it be easier?

[tcns]

It would look very strange most qlders are already anywhere from 1m - 2m off the ground, there are regulations that stop us from building over 8.75M (from memory) so that really isn't an option.


Tom

[reeves]

planning and execution mate. If u tale into consideration ALL ther variables, plan well and be carefull u should be ok.

However if r impulsive, unprepared, underskilled, unertooled, dont think about possible issues arising and take shortcuts, u will be in a far worse situation.

Get some good good advice and good luck.

regards
john

[Kenchiku]

Thanks Mick for the advice,

I too think it is a job for professionals. I've heard of house breaking in two so I'll stay away from that.

Cape crusader, my plan has not evolved so much yet, still at the Sketch Design stage. But I am thinking of doing a timber floor rather than a slab just because timber may be nicer and I figure I can put a few bearers,joists and floorboards down (I built a carport so I have a bit of confidence now). Then the framing then cladding. I have to do a lot of research on the detailing of the joints ect.
Actually the more I wite about this the more daunting it seems. I have a wife and 2 kids and a Job to compete for my time so this could be a long project.

If I was using recycled timber do I need special testing for it. I know if its hardwood or pine but how do I know if it's F14 ect. Is there a legal restriction with this?


Ken

[capedcrusader]

I have worked through a plan on the actual lifting


Hello Tcns
Sorry but I think I actually meant to ask you about how youre going to do the lifting- I guess its just a matter of ensuring it goes up evenly right? I thought I might make sockets for the ram part of the jacks and weld these onto the UBs and also maybe weld the jacks to a larger steel base for stability. I was also going to suggest that you make sure that the top plate halved corner joints between the main walls and between any load bearing cross walls are still intact (mine werent) although if the galv roof sheeting is still on there would be a fair amount of bracing there. Id be interested to see the new thread as it progresses anyway.
Kenchiku you inspect timber for obvious visible defects - old and dried good species hardwood without defects should be very strong as long as its not so dry that it has become brittle ie:some of the softwood that comes from roof spaces etc in my limited experience has been very dry /almost brittle. Although the way the timber has been loaded previously (ie: dynamic) might affect its strength - not sure - someone else might know. For any application seriously structural however you might want to leave the defect inspection to a timberyard but unfortunately its not generally available dried beyond 45mm thickness.
Cheers

[Harry72]

It would look very strange most qlders are already anywhere from 1m - 2m off the ground, there are regulations that stop us from building over 8.75M (from memory) so that really isn't an option.


Tom How do they build two story house's then, most would be higher than 8750mm.
The SWMBO parents last house was over 10000mm high, it would depend on local laws.

[tcns]

How do they build two story house's then, most would be higher than 8750mm.
The SWMBO parents last house was over 10000mm high, it would depend on local laws.
I think a picture would be the go,

The queenslanders as they stand are ususally between 600mm - 2000mm off the ground already - so if you plonked another house on top it would look very much out of proportion and even at 10m you would be lucky to get two stories + the distance off the ground within the bounds of the local law.

That and it would look hideous - it's a qld thing we raise them and build in underneather.

During more research I have found this company http://boothshire.com.au/propsaccess_propping.html

Who do hire out sleepers, jacks, props and bracing equipment.

I haven't priced anything yet but they look like they would have just about everything you would need.

Tom

[Hofmann]

I'm interested in doing a similar thing with my house except that its anormal weatherboard house in Newcastle. The house is about 1500 high at the back and 400 at the front.I have extensive views especialy if I go up. The reason I want to lift and build under instead of building on top are 1.downstairs I want a large amount of garage space and Im not keen on tearing out perfectly good and expensive to finish bedrooms to acommodate this.2.I get a finished, self contained, rentable flat upstairs and my wife and I can live downstairs next to my beloved garages. Iwant to design the stairs so that it can be lived in as one house,flats,flat and business etc for maximum resale appeal.3.Im not too keen on the present condition of my footings and dont reckon theyll take another story.This way,I can lift,put in permanent steel posts in on original footings,get the lifting gear out and pour a slab around the posts.Slab will probably be partly suspended.Any thoughts? Im a second year carpenter apprentice and Im also doing cert iv.I'm not even considering doing the lift myself but I want to detail this process for my cert iv build studies asignment. Does anyone know where i can find this info?