Pinning/Underpinning walls

Cuauhtemoc

Couple of questions on renovation.

Anyone have a rough or very rough approximate of how much it costs to pin walls?
This is a two story 100+ year old farmhouse(sort of reasonable state of repair but not habitable)
There are some cracks in the walls and we think we might need to pin them. Our structural surveyor hasn't been out yet.

Also may need to underpin the walls as well. I think i heard somewhere that this could cost 50 euro a meter(could be totally wrong there). Any rough ideas on this cost as well?

Many thanks for any assistance.

C.

mad m

Under pinning is a big job.Id wait till your engineer has a look.Only way to know for sure if walls need under pinning is to dig down to foundations and have a look or you can get kits to tell you if there is movement in the walls.

This comprises of very thin sheet of glass with holes so you can nail on either side of crack, and after a time if glass cracks then you know there is movement.Under pinning is done by digging down below foundations and pouring concrete in under that and putting re-enforced steel bars in also.

narommy

My personal opinion is that it would be madness to underpin a 100 year old farm house.

Once you start working on older properties it will through up many issues and you will probably wish you knocked in the first place. If it's only going to cost. An engineer might advise you to underpin it because it will make a lot of work for him

You could have a nice new warm house for not much more by demolishing it.

rooferPete

Hi,

I reckon you are missing a zero on that price, even back when we had the Punt that would have been cheap.

Your Structural Engineer will do up a scope of the works required and when excavations begin it will all change as the ground is exposed, some change for the better some worse.

Until you know what caused the problem and what needs to be done there are too many variables to start guessing at prices, don't forget you may need a new damp course as well.

narromy,

We can't go around knocking everything down just because of money, I would prefer the 100 > 200 year old building any day any time over the new buildings.

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Cuauhtemoc

Thanks for the replies.

If you saw the house you wouldn't want to knock it. Has great potential. Fairly substantial building and was lived in until 2 years ago(without running water and electricity believe it or not).
So could be 500+ a meter for underpinning?

What about tying the walls together? Any approx cost for that?
Obviously depends on a lot of factors but any rough approx to give me an idea.

@rooferpete.
I'd imagine we'll have to put in a dpc(though looks quite dry) so it'll be factored in to the budget.

Cheers.

beolight

what about steel frame inside the walls ties in everything and with new concrete base/footing for the girders your ready to go

narommy

Ok

I jumped the gun a bit.
It sounded to me like it was a bog standard farm house.
And I also didn't notice that the house is in Wicklow.


Pete,
Can you really say that you would prefer to live in a 100-200 year old house than a properly constructed new house? I lived the first 20 years of my life in one and would prefer a new one. My dad had a bit of a fire in his house a couple of months back and got a friend/builder in to fix it up. Once you start on an old house the work mushrooms if you want to do it properly. I just thinsk that people should be aware of this cost of living in an older house although I will phrase my comments better in the future

John

lomb

older houses are worth alot more than new ones. look what u pay in ranelagh or rathmines to live in a 150 year old house. a modest terraced house without car parking is nearly 2 million..

rooferPete

Hi,

Yep, crazy as it may read but I am in the process of buying one, it's a long process but I am willing to wait.

The modern house I am in was built in 1990 and I swore never again would I buy a modern house, this one is about as far from Dublin as I can realistically afford to travel so no 1.5 million outlay

The walls can be stitched using stainless steel pins and they will not be seen, a large part of the restoration process is undoing the bad work done in what at the time would have been "Good Faith".

Back to the lime mortar skills and those pleasure to work with Blue Bangor Slates what many people don't realise is the very thick walls of a stone built house have a large element of insulation by default.

The inside will be modernised and a lot of further insulation in dry lining and then I have the sash windows a job for Kadman

.

antoinolachtnai

One thing with old houses: don't renew stuff or get into big engineering work just because there's a few doors off true and a few cracks. Just because a wall has fallen a bit over the years doesn't (necessarily) mean that it should be underpinned. It could well be that it's fallen as far as it's going to fall. Underpinning it isn't going to bring it back into position anyway and you are never going to be able to turn an old house into a new one. If the house has been there 150 years already, it is unlikely to be about to fall down or become unlivable (providing there's not major rot in the woodwork and there's no major damp problem).

The following is a general remark rather than anything specific to you. If you are planning major renovation work, I would say that it is important to be true to the original nature of the building and not try to impose your will too much on an old house. You can tweak it a bit and change it around to suit your needs, but it is what it is, cracks and all. If the old house isn't really isn't what you want, then you'd be better to do like the man said and get a nice new one. It will save you time and money.

Do your research about stuff like damp proof courses. I wouldn't be nearly as knowledgeable as Pete, but I have read a little on the subject and I'm not convinced that retrofitted DPCs are necessarily all that effective. Whatever you do, don't *assume* that you need a new DPC, or that the first DPC system recommended to you is the right one for your situation. There have been dry houses in existence for thousands of years, some even dating from before the time when plastic and central heating were readily available. A lot (though by no means all) of these guys who were building houses in the 19th century really knew what they were doing. There are supposed to be seashells eight feet under my old house, but the basement floor is still reasonably dry.

I don't know much about this house of yours, but I would try to make sure you pay as much attention to the roof and the external walls as you are paying to the foundations. If there are damp areas in your house there is a good chance it is coming from problems in the walls and the roof rather than the ground up (assuming your house isn't built in very low ground).

Of course this is all fireside chat, you really need to ask your SE and some people whose opinion you can trust and who have actually seen the house.

Pete: dry lining - sounds like a brilliant idea, but is it? if you are interested in energy efficiency I would think about whether dry-lining and insulating the south-facing walls is a good idea. The new-fangled trend is that the thick walls should serve as a store of heat to warm the house during the evening. In new builds, the trend seems to be to put insulation as close as possible to the outside rather than the inside of the building for this reason. In this view of the world, internal dry-lining and insulation actually reduces the thermal efficiency of the building.

My unasked-for advice is that it is important not to over-modernise an old building. If you seal it up and insulate it too well, you will have condensation problems. These houses were designed to be highly ventilated! That's one of the reasons why they built them with those yokes sticking up in the middle of the roof. I suppose you could manage this by using one of those exchanger systems, but that really would be a radical change to make to an old house.

Good luck with the old houses folks! A lifetime of crawling round in basement and attic cavities, and all for the sake of five minutes of fumbled pleasure in an auction room! (I've done it myself, wouldn't change it for anything.)

rooferPete

Hi Antoin,

I am going to be very careful about what is drylined and what is left as is, I fully agree with you, the door off plumb only adds character, how many of the new builds are true to the eye, the level and the plumb

One job I have to do is remove a new (30 year old) plaster and dashing from the outside and repoint it with lime, I'm not sure what I'll find under the plaster so I may have to give a coat of lime plaster.

The old walls were meant to breathe and cement stops that process, the roof is original and very true but the nails are gone, I will have to use a breather membrane instead of felt and maybe a few ridge vents.

I love your last sentence

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Cuauhtemoc

Thanks for all the info.

We'll be trying not to change the character too much(though i've already smacked my head several times off the low door frames )
It's not actually ours yet but we're in a good position with the bidding and keeping fingers crossed.

Hopefully we can stitch the walls then. Sounds a bit cheaper than underpinning.

As an aside(this might be better in another thread) what are peoples opinions of ICF(insulating concrete formwork) offered by the likes of Polarwall and Termonex?
We might be considering a basement under an outbuilding(needs to be knocked) attached to the house. It would keep the original shape of the buildings and not change the character too much while giving us more space.

ICF is supposed to be ideal for basements and we could also use it for rebuilding the outbuilding. It has excellent insulating properties(according to manufacturers anyway) and very quick to build with but someone over on the constructireland forums reckoned you'd lose out on the walls being a thermal store as there is heavy insulation on either side of it.

Any thoughts?

C.

Victor

Cuauhtemoc wrote:

Also may need to underpin the walls as well. I think i heard somewhere that this could cost 50 euro a meter(could be totally wrong there). Any rough ideas on this cost as well?

I think for underpinning you should be thinking in the order of €1,000/m + repairs + damp treatment + work to floor slabs.

Tieing / pinning parts of walls can cost anything, depending on the nature of the crack.

Often the damp treatment has as much to do with rotten timber as actual dampness.

rooferPete

Hi,

Basements, even new ones can be a nightmare if not waterproofed properly, I have fitted an SBS membrane on the sub floors and brought the membrane outside the walls.

After the blocks went up, I had to prime them and bond the membrane to blocks then carry it up above ground level, nothing easy or fast about it.

Then there was a high density insulation board stuck to the waterproofing followed by a polyester mat to protect the waterproofing, then it was back filled.

The water pressure against the walls and floors of basements is a different animal to a standard roof, waterproofing on the inside is not really recommended, it's best to prevent it from getting near the finish if possible and it must be flexible to allow for settlement.

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Cuauhtemoc

Maybe a mod could split this basement stuff to a new thread.?

@rooferpete
So you'd see problems then with an icf basement then?

The structure is not flexible. Its effectively a single pour of concrete into the shape of the basement.

But this would give it a lot of strength would it not? From their faq below it would appear that they reinforce basement structures.

Can basements be built with Polarwall?

Yes: Polarwall is perfect for building retaining walls such as basements. The product will allow the concrete core in between the insulation to be increased from 150mm (6”) to 300mm (12”). Therefore reinforcing steel can be placed inside the wall with sufficient room for the concrete to cover the steel.

Adequate tanking must be installed as per the manufacturers instructions to prevent the passage of moisture through the wall.

When comparing the cost of traditional formwork or the time to construct a retaining wall using dense blocks, Polarwall provides an ideal solution to an ever-popular design concept.

Also they claim that the Extruded Polystyrene(XPS) that they use is "Virtually Waterproof"
From their website..

Watertight advantage – XPS is virtually waterproof whereas EPS will allow moisture to be absorbed over a period of time

Although they say it's totally waterproof in the FAQ on the site.



From everything i've read it seems to be a good way of building but i'd like personal experiences if anyone has any.

Cheers,

C.

Cuauhtemoc

@Victor

So to underpin the approx 40 metres of external wall would be about 40K?
Plus all the other work.
Hopefully it doesn't come to that then. Will have to wait for surveyors report i suppose.

Cheers.

C.

rooferPete

Hi,

One sentence copied from the first quotation :

Adequate tanking must be installed as per the manufacturers instructions to prevent the passage of moisture through the wall.

That's the detail I was referring to, it looks like they are contradicting themselves, why use any other Tanking Method if their product is waterproof ?

.

Cuauhtemoc

Hmm. I didn't pick up that when i was reading it. I can raise it with them and see what they say about it.
Will have to do more research in any case and price up all the various options. May prove to be too expensive to put in a basement, but we'll see.

Cheers for all the info.

C.