Re-Piling - Lift the House ? Dig a trench ? or Through the Floor ?

[FeverPitch]

Hi

I moved in to a 100 year old house back in October and in the process of installing under floor insulation I've noticed a large number of piles are bricks piled on top of each other - like a bad Jenga game.

Half the house is in-accessible some areas you can't even crawl under with the belly of the house almost touching the soil. Already had one quote which was to dig up the floor (107m2) $18,000 - 2 week job. The property is newly renovated so it would be a real shame to do this .

The existing outer piles don't look too bad and the floor is extremely level but something that needs to be done.

Does anyone have any experience in having their house lifted or a trench dug out as an alternative to digging up the floor ? Was it successful and cost less than say digging up all the floor ?

Many thanks FeverPitch
ps Yes I building inspector didn't pick up on this.

[jimO]

where are you, these people work in Dunedin and ChCh....http://www.southernrepiling.co.nz/

[FeverPitch]

where are you, these people work in Dunedin and ChCh....http://www.southernrepiling.co.nz/

thanks JimO I'm actually in Wellington. I've had one guy through quoting me the dig the floor up quote got another fella through this Saturday.

[Scave]

We are in a very similar situation with very limited space under half of the house. The piling guys we're about to use are going to have a go at doing it from underneath the house regardless. I was surprised at how small a space they reckon they can get into to dig out the holes. We've been quoted $13,000 for the equivalent size house in Auckland. Will let you know how successful they are (before recommending them), still awaiting council consent before proceeding (you'll probably need that too?).

I would get some other quotes if I were you.

[FeverPitch]

Thanks for the reply. The house is on pretty level ground with various undulations. The entry point is almost stand up size the previous owner re-did the piles there. But inaccessible parts were either left or stacked up with bricks. Lesson learnt. a pile specialist is coming Saturday that apparently dig trenches. But I'll be blitzing them with lots of questions.
1. What will it do to the windows (warping) ?
2. Will paint and wall paper crack around the walls
3. Will the house be higher than before so need to add extra steps to front and back of house ?
4. Can we install under floor insulation at the same time
5. Can we get those extra electrical jobs done too

We could go ahead and get this all done while we are on holiday but I think its important to be available for supervision and questions.

I heard only qualified builders can perform pile renovations. Although one of the builders websites they say if you have all the qualifications you don't need council compliance. Either way I think I'd still seek council compliance.

I would love to hear how you get on to please keep me informed - many thanks !!!

[Scave]

If your house is already level, I would hope you would get minimal movement and therefore minimal wall damage or window warping.
We intend to install insulation after the piling guys have been and gone, that said, if you have any areas that truely are inaccessible (and they have to lift parts of the floor) - then you'll want to get those done at the time.

In Auckland, I understand you can not replace more than 4 piles without requiring a building consent. 4 or less is considered "maintenance".

Good luck.

[Nice]

John Wilson Repiling is pretty experienced in old Wellington repiles.

Levelling is different from re-piling, may not need to be done if you don't want it, and that is the bit that cracks walls and stuffs windows etc.

John will get the consent issues sorted for you; and he should also recommend which way to go, through the floor or trench, and be able to price it accordingly.

Get multiple quotes, I would be interested in your result, as to who you decide to use and why ?

[FeverPitch]

John Wilson Repiling is pretty experienced in old Wellington repiles.

Levelling is different from re-piling, may not need to be done if you don't want it, and that is the bit that cracks walls and stuffs windows etc.

John will get the consent issues sorted for you; and he should also recommend which way to go, through the floor or trench, and be able to price it accordingly.

Get multiple quotes, I would be interested in your result, as to who you decide to use and why ?

Sure thanks for your reply ... I will update this post when I have made some progress.

[donnyboy]

Get polyester underfloor product called "Mammoth" friction fit between joists. If the guys need to remove a few pieces they can put back no problem. From most hardware stores now I would imagine.

[garrett]

Generally lifting the house is cheaper than digging out the ground underneath. Unless you have to do a fair bit of digging just to be able to lift the house.

Lifting the floor and digging out from inside the house may be cheaper if floors are particle board with carpet over (or similarly easily reinstalled products).

If floors are polished timber (especially native) or tiled membrane wet areas then forget lifting them to dig, far too expensive reinstalling them.

In lifting a house - strong backs are inserted underneath the bearers and then slowly jacked up to lift the entire house so there is enough room to do the work. There are very good and very bad operators and I have seen the results of bad operators and it was not pretty (total replacement of internal linings required).

When lifting you can expect some racking of the frame to occur and you will get plasterboard cracking at joints, especially if the plasterboard has been cut so a joint is at a window corner. Plastering and painting of some walls and ceilings may be required which is a shame if recently renovated. This is totally dependant on your operator.

If only part of the house needs to be repiled then digging underneath may be the lowest cost as there should be no repairs to internal linings.

I would ask for prices for all 3 methods, it may be a combination of lifting flooring to some rooms and digging from underneath may be the best option in lieu of lifting the entire house.

No matter which option you end up going with, you will need a building consent as it is work to the structure.

NZS3604 (the 1999 version, not sure about the latest) requires 300 mm clearance to bearers and a 450mm crawl space to be able to inspect all pile/bearer connections. So trenches 450mm deep every third row of piles to allow inspection would do that, assuming you manage 300mm clearance everywhere else. Bearers can be closer to the ground if you increase the bearer treatment from H3.2 to H4 or H5. Note that any fixings (pile/bearer connections) within 600mm of the ground should be stainless steel not galv. If the entire house is lifted so all bearers have 600mm clearance then all connections can be galv (except in a sea spray or corrosion zone).

Make sure your contractor does an overall piling plan for the consent that ensures earthquake and wind bracing requirements are satisfied.

One last thing - I recommend installing polythene (250 micron thick) to the entire subfloor that is wrapped and taped around each pile. The average 100m2 house can lift 40 litres of water per day from the soil underneath and the polythene can stop that and is really cheap. It also makes crawling underneath in future much easier and far less dirtier.

Good luck.

[FeverPitch]

Thank you for the info Garrett very useful. Yes it would be a shame to pull the floor as everything has been renovated . The floor is polished native wood and I can't see how it would be an easy job to replace this. The bedrooms are carpet but still an upheaval. We had another Re-piling expert come last Saturday he recommended trench digging rather than removing floors.

Obvious benefits are we don't have to move out and the disruption is minimal. Our floor doesn't require revelling and he pointed out walls and windows shall remain as is - a like for like.

Like you say he will dig numerous trenches. The quote given was $18,000 (inc GST) for a 107 m2 home two and half week job - two thousand more than having the floor removed. I'm still in a state of shock .

The quote is also quite vague as it states the price can easily rise depending on the need for more trench work and if there's the discovery of rotten floor boards. Earth disposal is extra but no figure given.

If you are that good with a lot of experience surely you can give an accurate quote.

It sounds to me $18,000 is a starting point and could easily rise which makes a farce to the original quote.

We have an a window frame and roof that needs replacing due to bad leak. But feel the piles are the first than that has to happen.

Not getting too carried away what is the worse that can happen ? The house has been standing for 107 years and most probably stand for another - it feels very solid. It could be left and when we come to sell it'll just be worked in to the sale price.

Earthquake is the biggest concern but its not hanging from a hill and already very close to the ground. So I could deal with it when something happens.

The cost is something we just can't afford.
thanks Fever.

[Maccachic]

Roof leak would be my main concern - is it getting into framing timbers?

[FeverPitch]

Roof leak would be my main concern - is it getting into framing timbers?

It has done. The water has been coming through the timber wall. We have a new roof for 90% of the house. For some reason the extra add on room only has a patched up roof. The temporary plastic sheeting is working well at the moment.

In addition the window frame during the previous (owners) renovation was cut where there was rotten wood, then sanded and painted. Meaning there's gaps in the frame and also in the putty. So rain in a South easterly comes dripping in.

The roof we are going ahead regardless. But we don't know whether we should do the piles first before the window replacement.

[garrett]

It has done. The water has been coming through the timber wall. We have a new roof for 90% of the house. For some reason the extra add on room only has a patched up roof. The temporary plastic sheeting is working well at the moment.

In addition the window frame during the previous (owners) renovation was cut where there was rotten wood, then sanded and painted. Meaning there's gaps in the frame and also in the putty. So rain in a South easterly comes dripping in.

The roof we are going ahead regardless. But we don't know whether we should do the piles first before the window replacement.

Fix the leaks first. Continued leaking will increase damage from decay to framing and will therefore increase in cost the longer you leave it.

You are absolutely right about your piles, they have sat for 100 or so years so far and being stacked brick will not decay in a hurry. The danger you have is the earthquake risk, but being timber framed and close to the ground (and I assume single level) the risk is to the house itself with a low likelihood of injury to occupants except from falling items.

An old school fix I have seen many times is number 8 wire looped around and around each stack of bricks and the bearer that lands on it just in case you get a sideways jolt.

When you can afford to fix the piles, ask for a proposed scope of works with all items listed that will need to be done including applying for the CCC from council.

Then ask for a lump sum price for the lot. With a job like yours the risk of fixing the price to the contractor is very low and there is no reason they shouldn't do it. If they are worried about rocks buried in the soil increasing the work you could negotiate that as a separate item and have that as a GMP (Guaranteed Maximum Price). So your listed scope of work (except soil conditions) would be a set fixed price, then the soil conditions item would be a separate fixed price unless rocks or otherwise are found, then you pay an hourly rate over the starting sum up to the GMP. If it is only a few extra hours then you haven't overpriced it to start with, if it is a considerable amount of work then you at least have a total fixed price that it can not go over.

My advice - fix the roof first, then the window, then the piles.

Cheers

[Janey]

Repiled my house last year via floor cutting and made it permanently unable to have nice polished floor ever (and some minor rodent problems during that 2 weeks ) so I had to put new flooring over the top. I didn't have much options as there was access problems so the house cannot be lifted, and it sits on some rocks so digging was not a cheap option. My house was pretty crooked and unleveled so had to adjust the height of new piles to level. And afterwards house's side frame settled a bit but nothing really cracked. Would like to know how you go though as I have another property in a more similar situation.