17th Century Timber framed house - breathability

[dans]

Fantastic Zebra! Very interesting, as I will be doing the same very shortly!

I'm having new windows put in within the next 6 weeks, where I expect a lot of the cement render to just fall off anyway! We'll peel the rest off then get on with insulating and re-rendering in Lime.

Were your red bricks exposed, or were they also rendered/painted? I also have a ground floor with solid brick walls, but they are covered in thick paint. I plan to strip back the paint and wondered how you did yours?

 

[dans]

Current House:

Planned appearance!

 

[Penners]

I shall keep going if I keep getting all this praise on here, it's getting quite addictive!

We're praising Henry, not you!

 

[Penners]

Planned appearance!

Dans, I recommend that you avoid having the lawn growing up the wall. It's rather unsightly, and tends to give the moles a headache.

 

[Zebra]

We're praising Henry, not you!

Ah yes, my friend and companion in all my cement-removing adventures.

Were your red bricks exposed, or were they also rendered/painted? I also have a ground floor with solid brick walls, but they are covered in thick paint. I plan to strip back the paint and wondered how you did yours?

The red bricks were also covered with cement render. The whole house, inside and out, was covered with cement render. I chipped it off last summer, with not too much damage to the bricks. So can't help with paint stripping I'm afraid.
What are you planning to insulate with?

 

[Zebra]

I've taken the render off the front elevation, and the timber is in quite bad condition. The rot goes further than on the other elevations. Also, the window frame has been built in modern timber. And this is where I did my repair (see http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=12565&hilit=+timber+frame+repair) which at the time I though looked great, but now I'm not so sure, as what it's screwed to isn't up to much. All of the uprights are rotten at the ends. All of it is loose.

Here's the area in question (it perhaps looks a little better than it is because it's just had a coating of pemethrin):


I'm considering redoing the whole elevation in reclaimed timber. What other options do I have? I could put new modern timbers in alongside them? I could save some of them by cutting down the larger pieces and make smaller pieces of them? Extend the mortices so that I can shift all the uprights along a bit, cutting off their rotten ends?

 

[Penners]

I'm considering redoing the whole elevation in reclaimed timber. What other options do I have?

The other option that you have is to rebuild that part of the frame in new, green oak. It's an "honest" repair that will look great and will contribute to the long-term future of the house. And, as the oak is green, it will be much easier to work than reclaimed old stuff.

I can't remember whether you're listed or not - if so, then maybe just make a quick phone call to your CO. I'm confident he/she will be happy with this.

 

[tobydog]

I second Penners view on using green oak. All the advice I have seen and read recommends the same for the reasons given. The thing with green oak though is that you may have ongoing movement for a while during the drying / seasoning process that may need remedial work until it settles.

 

[Penners]

Well yes, that's true. But I've done several such jobs in green oak, and the remedial work has never amounted to more than a bit of filling and paintwork retouching.

 

[Zebra]

No, I'm not listed..... The timber frame is not revealed on either the inside or the outside. So the appearance isn't such an issue as it might be. Isn't the problem with green oak that it shrinks? So if I make the timber uprights nice and tight now, in two year's time they'll be loose - given that none of the rest of the frame around them will be shrinking?

 

[dans]

Any timber frame repairs I've had carried out so far has been under instruction by my structural engineer who has always specified air dried oak 3+ years. I bought a large 3m length of 10 year oak for £108 from a local timber merchant in Thetford.

 

[Penners]

Isn't the problem with green oak that it shrinks? So if I make the timber uprights nice and tight now, in two year's time they'll be loose - given that none of the rest of the frame around them will be shrinking?

Green oak shrinks, but not along the grain (to any appreciable extent). Across the grain (depending on its original moisture content) it may shrink by 8 - 10%. So your timber uprights aren't going to get any shorter, but they may get a little thinner - hence my comment above about a bit of filling. So, for the sake of argument, if your new green oak studs start out 100mm wide, they may shrink (over the space of several years) by about 10mm on their width and a roughly similar proportion on their depth. On their length, however, no appreciable shrinkage will occur.

 

[Zebra]

OK. Sounds like a good idea then. Thanks!

 

[middi]

No, I'm not listed..... The timber frame is not revealed on either the inside or the outside. So the appearance isn't such an issue as it might be. Isn't the problem with green oak that it shrinks? So if I make the timber uprights nice and tight now, in two year's time they'll be loose - given that none of the rest of the frame around them will be shrinking?

There are a lots of valid and necessary reasons for using green oak when repairing and old oak framed building

1) it is easier to work with ( as Penners pointed out)
2) there are no old nails etc.. in new oak that could ruin you tools
2) contrary to some belief that green oak will become loose when inserted in old oak mortices due to shrinkage it will actually have an opposite effect, yes new oak will shrink but it will also twist, it is the twisting action that will lock the oak studs within the mortices and not necessarely the tight fit within the mortice.
4) using old oak in an existing historic building it will confuse the issue if future historians need to date the repair or the age of the building, this is why any repairs to oak frames should be dated with marks on the new frame or replaced componenets.

Middi

 

[FamilyWiggs]

No, I'm not listed..... The timber frame is not revealed on either the inside or the outside. So the appearance isn't such an issue as it might be. Isn't the problem with green oak that it shrinks? So if I make the timber uprights nice and tight now, in two year's time they'll be loose - given that none of the rest of the frame around them will be shrinking?

There are a lots of valid and necessary reasons for using green oak when repairing and old oak framed building

1) it is easier to work with ( as Penners pointed out)
2) there are no old nails etc.. in new oak that could ruin you tools
2) contrary to some belief that green oak will become loose when inserted in old oak mortices due to shrinkage it will actually have an opposite effect, yes new oak will shrink but it will also twist, it is the twisting action that will lock the oak studs within the mortices and not necessarely the tight fit within the mortice.
4) using old oak in an existing historic building it will confuse the issue if future historians need to date the repair or the age of the building, this is why any repairs to oak frames should be dated with marks on the new frame or replaced componenets.

Middi

5) it is cheaper than 10 year air-dried oak.

 

[Zebra]

It must be indeed! I just phoned a local mill. They'll supply enough timber to replace the whole elevation for £45 + VAT!

 

[MdB]

It must be indeed! I just phoned a local mill. They'll supply enough timber to replace the whole elevation for £45 + VAT!

So that is the delivery cost. How much for the oak?

 

[Penners]

Zebra - I must agree with MdB's dry remark. That sounds incredibly cheap - are you quite sure that price covers all the sawn green oak that you need?

 

[Zebra]

No indeed I am not sure! I had to question the price with the bloke on the phone - he said "You're talking to a mill not a merchant!" The existing wall studs are not uniformly sized, the width average 60mm (range 50mm to 80mm) and the depth average 80mm (range 60mm to 95mm) so I asked the mill to price for 3 x 2 - perhaps this is too small, I will check again what sizes they can do. In terms of length, I was planning to reuse some of the timber, so I estimated that I would need:
2 @ 1800mm
2 @ 1550mm
2 @ 1100mm
2 @ 1000mm
but again, I need to check this. There wouldn't need to be a delivery charge, I could go pick it up.

I think what I will do is remove the final elevation of cement render, and make a full proper list of the timber I need! I'll let you know what it comes to!

 

[MdB]

It sounds about right actually.

https://www.google.co.uk/search?q=50mm+x+75mm+x+2+x+(1.8m+++1.55m+++1.1m+++1m)+x+£1100/(m+x+m+x+m)

£1100/m^3

I've been quoted a bit higher than that locally but I need larger cross sections and lengths.

For comparison my seasoned T&G oak floorboards work out at £1400/m^3 which is a good price.