Advice: Extending a house over drains; subsidence near trees
Discussion
Hello forum!
looking for advice from PH hive mind...
We're after the next step house, have been for ages. Recently, a house has come up that we're really interested about, but also really scared about..
House as it is:
Total house c. 2300 sq ft, but 300 sq ft is a single story extension.
Single story side extension is subsiding. Engineers report says due to the "f
k off massive tree" that's c. 4m away but also under TPO. When I say massive, it's >5 stories height, judging from street view.
Conclusion of engineers report in selling pack: Underpinning / piling, but more economical to rebuild.
Meanwhile, a mate of mine tells me not so simple (can't dig a trench in root zone, can't risk lie of tree, he gave up on application).
Plot is wonderful; totally ticks the "location, location", massive, established walled garden, most of which is sadly TPO'd but the kids would have meters of "den" to play with.
To make house what we want, would need 2 stories extension rebuild on footprint of side extension, plus c. 3m single story across the whole back of house inc extension. Main drain runs parallel c. 2.5m - 3m away from back of house. More fun.
Naturally, with all of this, the house is going well under local market rate for similar houses. We could theoretically buy with no mortgage, by taking current house value plus all savings. Would need to remortgage to do the extensions. I think the struggle to mortgage a subsiding building is also how it's the price it is.
So - PH massive...
How much of a ballache is build over sewer?
How much of a ballache is building with piling in root area of a TPO'd massive tree?
Can you tell me if this is madness or genius?
Thanks in advane!
looking for advice from PH hive mind...
We're after the next step house, have been for ages. Recently, a house has come up that we're really interested about, but also really scared about..
House as it is:
Total house c. 2300 sq ft, but 300 sq ft is a single story extension.
Single story side extension is subsiding. Engineers report says due to the "f
k off massive tree" that's c. 4m away but also under TPO. When I say massive, it's >5 stories height, judging from street view. Conclusion of engineers report in selling pack: Underpinning / piling, but more economical to rebuild.
Meanwhile, a mate of mine tells me not so simple (can't dig a trench in root zone, can't risk lie of tree, he gave up on application).
Plot is wonderful; totally ticks the "location, location", massive, established walled garden, most of which is sadly TPO'd but the kids would have meters of "den" to play with.
To make house what we want, would need 2 stories extension rebuild on footprint of side extension, plus c. 3m single story across the whole back of house inc extension. Main drain runs parallel c. 2.5m - 3m away from back of house. More fun.
Naturally, with all of this, the house is going well under local market rate for similar houses. We could theoretically buy with no mortgage, by taking current house value plus all savings. Would need to remortgage to do the extensions. I think the struggle to mortgage a subsiding building is also how it's the price it is.
So - PH massive...
How much of a ballache is build over sewer?
How much of a ballache is building with piling in root area of a TPO'd massive tree?
Can you tell me if this is madness or genius?
Thanks in advane!
well there are plenty of other houses to buy
if you really want it
make a TPO application for felling, use the engineer’s report i trust he has done some level monitoring to show the movement is seasonal and downward he may need to to persuade the LPA the tree is the cause of the damage
crack monitoring doesn’t tell the full story
the building is founded on a cohesive soil?
Movement should be recovering or recovered now and beginning a downward movement by late spring as leaves come into maturity progressin through the summer
It could be differential settlement due to the extension and the house being founded at different depths and movement at different rates??
What about the vendor, have they made a claim for subsidence with their buildings insurers and what was the outcome?
If the tpo app fails you can appeal but it isn’t quick
Tpo – 8 weeks determination
Appeal fk knows probably 35 weeks +
perhaps see above - buy another house
if you really want it
make a TPO application for felling, use the engineer’s report i trust he has done some level monitoring to show the movement is seasonal and downward he may need to to persuade the LPA the tree is the cause of the damage
crack monitoring doesn’t tell the full story
the building is founded on a cohesive soil?
Movement should be recovering or recovered now and beginning a downward movement by late spring as leaves come into maturity progressin through the summer
It could be differential settlement due to the extension and the house being founded at different depths and movement at different rates??
What about the vendor, have they made a claim for subsidence with their buildings insurers and what was the outcome?
If the tpo app fails you can appeal but it isn’t quick
Tpo – 8 weeks determination
Appeal f
k knows probably 35 weeks +perhaps see above - buy another house
Relativley simple to remove the existing extension, leaving its foundation in place, then install mini piles within the existing footprint. This should be acceptable to the tree officer. A raft foundation can then be installed to support the new extension cantilevering over the old foundation.
This avoids having to declare underpinning work to insurers or any future buyers.
This avoids having to declare underpinning work to insurers or any future buyers.
None of it is difficult, mini piling is the easiest solution. Water authority will ok a piled solution, piles will not affect the root zone and heave precautions to the piles and beams of the new foundations will sort out any potential clay heave or root influence to the build.
If you need an engineer to design founds and a company to price for the proposal just let me know. Over 20 years experience in this type of work (underpinning and mini piling).
If you need an engineer to design founds and a company to price for the proposal just let me know. Over 20 years experience in this type of work (underpinning and mini piling).
How deep are your pockets…? Extension costs are ridiculous at the moment. Will the works add significant value to the property compared to others on the street?
We are getting quotes of £3,500per sqm, not including VAT for single storey works at the minute.
Builder we spoke to today said he’s having projects cancelled as budgets set when architects drew up plans 6-12 months ago are now totally unaffordable.
We are getting quotes of £3,500per sqm, not including VAT for single storey works at the minute.
Builder we spoke to today said he’s having projects cancelled as budgets set when architects drew up plans 6-12 months ago are now totally unaffordable.
Some Gump said:
totally ticks the "location, location", massive, established walled garden, most of which is sadly TPO'd but the kids would have meters of "den" to play with.
Providing you have good builders none of what your describing is difficult, go for the demolition and rebuild option it will be quicker and cleaner. Our builders found a well when digging out new foundations on our build project, it delayed the project by a couple of weeks or so as we had to get the engineers out onsite and redo some foundations drawings.As for the cost, it really depends on just how good a location it is. We lucked out with our purchase, work commute is 25 minutes on the pedal bike for me, 15 minutes for my wife, excellent state schools, big retail park 5 minutes drive away, walled garden with wood land protected by a Royal charter in the back garden so totally private, and we are in a conservation area so zero chance of new build going up that can over look any part of the house/plot. Best bit is we paid substantially less for a similar sized hended in new build house sitting on plots about 1/10 the size a few minutes down the road.
The reasons the house was cheap was partly down to the market when we bought but also down to the fact it was a 1960s bungalow that had been extended multiple times and clearly needed some building works doing. It's now coming up to a decade since we first moved in, and in that time no other house on the street has come on the market, and given the rate new builds are going up nearby and their ridiculous asking prices anything that comes up for sale now in the village will be snapped up in a heart beat. It's sounds like you have more than enough do the required building works needed.
Location, location, location, houses can be changed quite easily (assuming you can afford the building costs), the plot and location cannot. We ended up doing some very extensive building works to ours, zero regrets, and we feel really previllaged to now live in a home that really is unique and built to suite our needs, if really does put a smile on my face to come home every day
.Oh our total final bill for building costs from drawings to finally moving in was £2236/sq meter including VAT with the build completing in 2024, so costs will be higher now. We funded the build partly through a remortgage but rates at the time was sub 1.5% so almost free borrowing. We had no interest in DIYing any of the build, if you do works your self you can get the cost down, but we just wanted the project done ASAP.
Cost, quality, speed, no building project can achieve all 3, so pick one/two that's important to you, and be comfortable with slippillage on the others.
Edited by gangzoom on Saturday 14th March 06:33
Bear in mind planning trumps a tpo.
As such it maybe simpler to get rid of the tree in the new planning application citing property damage and th sole reason for th application being the need to deal with the damage.
As above asked by someone why has the owners existing insurer not deal with it ?
As such it maybe simpler to get rid of the tree in the new planning application citing property damage and th sole reason for th application being the need to deal with the damage.
As above asked by someone why has the owners existing insurer not deal with it ?
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