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Rob Irish
Posts: 225
Location: Estonia, Zone 5/6
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Hi everyone

We are working on an old brick barn here and putting a new roof on. The old one collapsed due to some past owners doing some hacky frame with either weak wood or the rafters were too small and far apart. They also didn't it seems attach tie beams to the log wall plates, instead did some bizarre steel piping tie beams which were cemented into the top bricks. So the roof, I'd say under snow load, pushed the rafters outwards. Anyways, long story short, we've taken off the roof and the first few top rows of bricks.

Due to time constraints and my poor planning, we're going to be purchasing the wood to make new rafters. I'll also be making new wall plates out of wood.

The bricks being used are Aeroc (see www.aeroc.eu) 600mm x 300mm x 200mm. It's some kind of cement with air bubbles in it. Very easy to cut through and drill into but is used extensively here in Estonia.

The dimensions of the building are 8m long by 6m wide. The pitch of the roof will be 8/12. It will be an open ceiling, with some sort of steel roof plates.

I've broken down the aspects of the work into the following:

Wall plates:
My initial thinking is to follow the same principles in log house building for the wall plates e.g. I would imagine something like 15cm lumber with half lap joints, but watching videos I see a lot of modern construction using much smaller pieces. What would you use?

Securing log wall plates
I would drill down into the top row of bricks and cement in some half inch threaded steel and lock the wall plates to the bricks like this. Is it suffice?

Tie beams
I have only really learned about log building, where tie beams are made of whole logs and they join into the wall plates, but looking at a lot of modern construction it seems they don't even use tie beams and just have ceiling joists. Are they making these ceiling joists act as tie beams?

Framing
Modern construction seems to use a lot of these metal plates to join rafters instead of traditional joinery. When I demolished the roof on the brick barn, the rafters had birdsmouth joints that sat on the wall plates. Are these birdsmouth what you use. How are they secured properly? Past builders here just secured them with nails which lended them to bending and slipping off the wall plate. I've seen some different kinds of anchors around the place for this. What do you use and why? What sort of size lumber do you use, and how far to space apart the rafters? And what is your preferred method of joining the rafters at the top? Do you bother with joints or do you just use a whole bunch of different metal plates/anchors with nails?

For example..


I'm really open to any ideas on what is the simplest most secure way forward. Appreciate any pointers, or if you could help and need anything from me please let me know.

Many thanks,
Rob
 
Jay C. White Cloud
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Hi Rob,

Good to here from you again and to see you are still busy working on everything...

The dimensions of the building are 8m long by 6m wide. The pitch of the roof will be 8/12. It will be an open ceiling, with some sort of steel roof plates.


Hmmm....lost me a bit on the "steel roof plates." Do you have a link to or a photo of this? I don't use much steel at all to build with, and only add it "afterward" to comply to PE spec, or some other mandate of silly modern "overkills," on load dynamics...or...to make something go faster and/or stronger. However this is usually in the way of "bake up" threaded rod" or "timber connecting" long screw/lag.

Wall plates:
My initial thinking is to follow the same principles in log house building for the wall plates e.g. I would imagine something like 15cm lumber with half lap joints, but watching videos I see a lot of modern construction using much smaller pieces. What would you use?


Sounds like a way to do it. I do see things well in my head from words alone, so would have to CAD model it out and or see some photos or sketches.

Securing log wall plates
I would drill down into the top row of bricks and cement in some half inch threaded steel and lock the wall plates to the bricks like this. Is it suffice?


That brick material, as I know it, is very friable and not really that strong a material. Threaded rod, even in solid concretes/stones, must be "epoxied in" with very specific epoxy types to meet the load specifications described above...Otherwise, traditional roofs just relied on being massively heavy timber, often with thick wood shake (on low pitch like the one you are working on) and "stone keepers" that sat on long riven pieces of wood that held the wood shakes on...

Tie beams
I have only really learned about log building, where tie beams are made of whole logs and they join into the wall plates, but looking at a lot of modern construction it seems they don't even use tie beams and just have ceiling joists. Are they making these ceiling joists act as tie beams?


They are making the ceiling joists the tie beams...I personally find most of this "stick building" practices very minimalistic and never as strong as traditional joinery systems, nor as enduring...

Modern construction seems to use a lot of these metal plates to join rafters instead of traditional joinery.


Yes they do!!

Which comes from losing the skill sets to build traditionally and the practice of "put another nail in it...to make it "seem" stronger." Much of this is what one of my old teachers would call "prayer work,"...meany the builder just prayed it was strong enough to do what they hoped it would do...

When I demolished the roof on the brick barn, the rafters had birdsmouth joints that sat on the wall plates. Are these birdsmouth what you use. How are they secured properly?


"Bird's mouth" joinery is just on of many systems of "common rafter to wall plate" joinery systems. Many just "sat" in the joint and where held in place by gravity. Others may have taken an "oblique trunnel/peg." Some got "lashed done"...which is very rustic but also very strong too. Somewhere embedded in "lime torching" which in turn also secure the first few courses of slate or stone...if that type of roofing material was employed...

What do you use and why?


Joinery, because that is just the way I have always done it, what I was taught, and I tend to build/make everything in a traditional format unless I can actually see/find a better way...Which is very seldom...

What sort of size lumber do you use, and how far to space apart the rafters?


This is highly dependant on the size of the structure, roof loads dynamics, span type, timber framing chosen, etc. In this projects case I would need to know if the walls still actually had structural integraty? Then I would probably still augment the wall with interior post framing. It is spanning 6 m without a middle post so some form of "King" "Queen" or related double cord truss assembly would have to be used or a post in the center added. Timber/log size would start in the 150 mm to 200 mm range and go up from there...

what is your preferred method of joining the rafters at the top?


Most commonly for me (but I work mainly in Asian designs) is a simple "lap joint" in the "sill purlin" and "ridge purlin" beam (aka plates.) I may (or may not) go back and secure with a "backup" metal drawing device like a "timber loc" or related fastener....

Do you bother with joints or do you just use a whole bunch of different metal plates/anchors with nails?


I never use nails, and the last time I pounded in a "spike" it was a replica from 350 years ago that was hand forged by a local blacksmith for a restoration project. I use all wood joinery for 99.9% of my work. Much of this can be found online with photos. Let me know if I can expand anything?

Regards,

j
 
Rob Irish
Posts: 225
Location: Estonia, Zone 5/6
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Thanks Jay - definitely keeping busy!!

I took photos of the process demolishing the barn and put them on my blog here.

As you can see I haven't taken down all the bricks. I tried to salvage / leave in place whichever ones I could. This was really tricky because the mortar / cement was tougher than the actual bricks. Which meant as I was chiseling out the bricks often the brick adjacent or below would crack. I can't say I am a fan of this material and it definitely is friable as you say. It is just the situation we are in now, if you read the blog, we don't have a winter ready house anymore and I'm in between a rock and hard place trying to work out what is the safest and fastest way moving forward. If I had the logs and time I think I would just remove all the bricks and put a log structure on top of the foundation.

When I said 'Steel roof plates', I meant tin sheeting. Sorry - what do you call them? Again, I would love to get a froe and make shingles, which is what I'm hoping to start doing for the log house, but unfortunately I think tin roof is the cheapest and easiest for me to install this time.

I was also thinking of adding additional support with post framing, but if the wall plates are sitting on the bricks, how do you join in the posts so that they support? Would you be able to rough sketch that? In my mind, they wouldn't be directly underneath the wall plate. I'm just trying to visualize how that would be done. The bricks and wall seem to still have integrity, but I don't trust them and I wouldn't want to rely on them solely for long.

Thanks for your help J. I'm going to researching some of these words you mentioned like the joints.

 
Mike Cantrell
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Location: Mid-Michigan
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Rob Irish wrote:
When I said 'Steel roof plates', I meant tin sheeting. Sorry - what do you call them? Again, I would love to get a froe and make shingles, which is what I'm hoping to start doing for the log house, but unfortunately I think tin roof is the cheapest and easiest for me to install this time.



In US English, we would call that "metal roofing".
There are different kinds of metal roofing:

corrugated metal roofing, http://www.costametals.com/images/portfolio/28.JPG

ribbed metal roofing, http://www.snoshield.com/wp-content/uploads/2014/02/rib-seam.jpg

and standing seam metal roofing, http://www.roofercalculator.com/wp-content/uploads/2011/10/standing-seam-metal-roof-installation.jpg


As a loose rule, we use "plate" for something that is flat and wide but rigid, and "sheet" for something that is flat and wide but flexible.

Hope that helps!
 
Rob Irish
Posts: 225
Location: Estonia, Zone 5/6
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Thanks, Mike!

I've usually called them metal roofing as well. Those loose rules are going to help a lot, though. Not sure where I picked that up. When I learned the top log was called a wall plate I think it threw me off and I looked up terms for other things and found roof plate somewhere.

I think we're going to opt for the ribbed metal roofing, or standing seam. Open to suggestions of course.



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