17th Century Timber framed house - breathability

[Zebra]

the internal fabric has to be breatheable to allow any moisture that has travelled as far as the shuttering play ( if used ) and the INNER face of the celotex to evaporate outwards

Sorry, what is shuttering play?

 

[Flyfisher]

Shuttering ply, methinks. Basically, plywood without a decorative veneer.

 

[Zebra]

Aaah, I see, it all makes sense...

 

[Zebra]

Would anyone happen to know a contractor in the Herts, Beds, Bucks area experienced in the application of wood fibre external wall insulation? Never met anyone who's ever used it before. Many thanks....

 

[Zebra]

Also, struggling to decide whether I would need to pay an architect £2000 or so to draw up the various junctions for me, or whether the technical person who comes to site when you buy this stuff (wood fibre external wall insulation e.g. Steico, Diffutherm, Gutex...) knows enough to be able to tell you how to do complicated junctions with adjoining roofs, flat roofs, etc. Anyone with any experience? Thanks.

 

[oxalto]

Zebra,
I'm not entirely sure if this will fit perfectly with what you want, but I have just used hemcrete as the infill in the timber frame area of my house. It will have lime render on the outside, hair plaster on the insider and is fully breathable. It also more than meets building regs. Do have a look at this link - I found the company to be great and they didn't mind my very small order and DIY installation!
http://www.limetechnology.co.uk/hemcrete.htm

 

[Zebra]

Sounds great. I'll give the company a ring tomorrow. I've kind of heard of Hemcrete but don't really know what it is. Is it a rigid board? Do you use it on the inside or the outside? Or both?

 

[Zebra]

Oh how weird. I'm just watching the Hemcrete video. You pour it behind shuttering around the frame! Not sure if that would work. Is yours an old house?

 

[oxalto]

Sounds great. I'll give the company a ring tomorrow. I've kind of heard of Hemcrete but don't really know what it is. Is it a rigid board? Do you use it on the inside or the outside? Or both?

It is a mixture of hemp (not the naughty kind) and lime mortar (powdered). You mix equal quantities of both, with some water, in a normal drum mixer or pan mixer if you can get hold of one, and then build it up by hand. You need to shutter first - I made big external ones out of ply cut to the quirky shapes of my panels (curved braces to get around etc!) and long horizontal straight ones for the inside about 30cm high at a time. The end result is a solid wall which looks wonderfully similar to the straw-based daub that is present in the unaltered parts of the room. I think 20cm thickness gives building regs but I went for 30cms as I had space to play with. I had originally considered wattle and daub followed by insulation but hemcrete does the whole thing in one go, is pretty quick to do and very lo-tech. As I say, we'll render the outside as we would have done anyway and plaster the inside as planned. The hemcrete gives an excellent key and can easily be cut afterwards if you want to make exciting shapes in the wall. You can also "cast" it into whatever shape you like so curves are an option If you like them. We've been so pleased that we're considering using it elsewhere in the house, but it seems most ideal for timber frame infilling.

 

[oxalto]

Oh how weird. I'm just watching the Hemcrete video. You pour it behind shuttering around the frame! Not sure if that would work. Is yours an old house?

Yes - 16th Century! The video is how to do it on a huge scale. Our version was much more domestic and involved carrying Sainsbury's troughs up our stairs! We had a lot of fun doing it!

 

[Zebra]

So you did it all in one continuous go? The wall is now Hemcrete out to in, with render on the outside and plaster on the inside, with the 16th C frame somewhere in the middle? Amazing!

 

[oxalto]

So you did it all in one continuous go? The wall is now Hemcrete out to in, with render on the outside and plaster on the inside, with the 16th C frame somewhere in the middle? Amazing!

Pretty much! The timber frame is actually visible from the outside as it is pretty, but it could just as easily have been on the inside (but then we'd have to have changed the roof eaves a bit). We're still waiting for it to dry before we can render the outside and plaster the inside. It has a great smell at the moment...

 

[Zebra]

Pictures! Please, pictures!!
So this stuff's clearly fully breathable then. And weatherproof?

 

[Zebra]

How strong is it? I don't know how able my frame would be to support itself and the roof without a racking / sheathing board. Does this stuff set hard enough to offer structural support to the frame? What was on your house before you put the hemcrete on? Did you strip it right back to the frame? The whole thing or a bit at a time?
How exciting.....

 

[Zebra]

Well, just wanted to share a bit of progress. I've stripped the cement render off one elevation, the gable end. Turned out the cement wasn't all that well attached to the frame, and the frame was pretty much OK.

Doesn't it look lovely. If only it could be kept like that, with the frame showing on the outside, it looks so pretty. But it will have a lime render instead of the cement.
In the foreground is the newly rebuilt side extension, awaiting its roof.
Oh, and before someone notices, I know that's not how you do loft insulation, I know you're supposed to roll it out, not just shove it in the loft....

 

[LadyArowana]

Doesn't it look lovely. If only it could be kept like that, with the frame showing on the outside, it looks so pretty.

It's only natural that you would like that black and white stripy look! :lol:

You are making great progress, congratulations, must be very pleasing to see the house coming back to life.

 

[FamilyWiggs]

Doesn't it look lovely.

It does indeed. Well done; the house is lucky to have found you.

 

[Zebra]

....two......

 

[JoceAndChris]

That does look lovely! Well done.

 

[Zebra]

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