A basic mill to make roof trusses

[Woodworks]

26 minutes ago, difflock said:

Nobody answered the question re Elm's suitability for trusses, which I suppose can only mean it will be OK?

Would imagine it would be a brave SE to pass standing dead wood for structural purposes. You dont know what killed it and how it may have affected the timbers strength.

[Squaredy]

9 minutes ago, Woodworks said:

Would imagine it would be a brave SE to pass standing dead wood for structural purposes. You dont know what killed it and how it may have affected the timbers strength.

I agree a structural engineer might be wary. In reality any skilled chippy should be able to judge timber strength and integrity. After all the mighty oak can have all manner of structural weaknesses. Whatever the species someone has to judge the strength of each beam which will be quite easy when milled. 

[Baldbloke]

Nobody answered the question re Elm's suitability for trusses, which I suppose can only mean it will be OK?

Dutch Elm disease.
I’ve cut about 90 cubes of this Elm already as firewood. The only suspect areas I have seen so far have been at some of the larger butts for up to a couple of foot from the base where some of the butts are pumped. The smaller trees don’t appear to have this rot in the centre of the trunk at their bases.
It was really the weight issue for handling as these trusses would be replacing the originals made from half trunks of softwood.
The wood appears very elastic and strong with no apparent boring or rot. The trees that are completely dead are without bark and very hard. They are still standing, mostly as single straight trunks up to 60/70 foot high.
I’ll just have to be careful in dropping them as they can break on hitting the ground. The best way appears to be to intentionally hang them up and then drag them off gently from the butt so they don’t hit the ground so hard.

I’ll try and get down to the wood to post some pictures

[Graham w]

your not going to have any problems with 8x5 elm where a modern build uses 45x100mm for the equivalent span. for good measure have the beams graded to rule out any flaws 

[Baldbloke]

your not going to have any problems with 8x5 elm where a modern build uses 45x100mm for the equivalent span. for good measure have the beams graded to rule out any flaws 

Sorry, what is graded?

[Baldbloke]

Hi
 
When are you planning the build? Im very busy Atm but could extract/mill/machine that timber fairly quickly for you and we have an automatic component saw to make all 60 trusses in minutes 
 
let me know if your stuck
 
Graham 

Hi Graham,

That’s good of you!

Extraction is tricky and time consuming as my wood is on a hill and it’s not clearfell.

My steading roof is hipped and the ends of the trusses do not sit on a wallplate but are built into the wall-and so probably too complicated to manufacture off site.
I’m envisaging a lot of Acrojacks and piecemeal replacement.
Here is some of the same wood. It appears 100% sound.
The existing trusses are largely made up of trunks split in half.
I’m hoping to emulate that for the replacements.

[Baldbloke]

I agree a structural engineer might be wary. In reality any skilled chippy should be able to judge timber strength and integrity. After all the mighty oak can have all manner of structural weaknesses. Whatever the species someone has to judge the strength of each beam which will be quite easy when milled. 

This Elm appears pretty sound. The maul is sitting in a lump of Elm which has had some serious abuse over the last month

[Baldbloke]

Hi Graham,

That’s good of you!

Extraction is tricky and time consuming as my wood is on a hill and it’s not clearfell.

My steading roof is hipped and the ends of the trusses do not sit on a wallplate but are built into the wall-and so probably too complicated to manufacture off site.
I’m envisaging a lot of Acrojacks and piecemeal replacement.
Here is some of the same wood. It appears 100% sound.
The existing trusses are largely made up of trunks split in half.
I’m hoping to emulate that for the replacements.

Where are you are based Graham?

[Graham w]

you can visually grade the timber or have it mechanically graded. for the size elm of beams you are using you would visually grade them (there is a thread on this somewhere) and this to separate the best beams from those that have flaws e.g. rot, cracks and excessive knots.

 

Im based in between Inverness and Nairn 

[Graham w]

3 hours ago, Squaredy said:

I agree a structural engineer might be wary. In reality any skilled chippy should be able to judge timber strength and integrity. After all the mighty oak can have all manner of structural weaknesses. Whatever the species someone has to judge the strength of each beam which will be quite easy when milled. 

This

Edited April 12, 2018 by Graham w