Roof and facia boards etc

[Deansocial]

1 problem with tanalised timber is all those popping screw head on the plasterboard because it is always soaking wet when it arrives. This is a warm roof so condensation will not be a problem.

 

[jmbfestool]

Ok... this may seem harsh but I would never cut a roof in the UK using untreated timbers.

Reason?    very simple,  the untreated rafters and roof members will have a short lifespan in comparison to treated timbers.
Bare minimum would be to install the wallplate using treated timber. I also sit my wallplates on DPC and then bed them in mortar. Years ago natural slate was used with the old lime mortar.

Wallplates if not sat on DPC will rot and decay first.

If you were to ask an Architect they would say use treated but Building control would give you the option not too (Then again they pass modern trusses!).

I have lots of experience with cut roofing and I do not claim to be an expert! but...I would strongly suggest treated timbers for cut roofing.
Some would argue about breathable felt being used would eradicate the problem of condensation etc but it does'nt solve it entirely. You could use untreated and spray them after with something like clear protim or just use tanalised form the start. Obviously C16 and C24 timbers depending on spans etc.
I suppose everyone has there own opinion on it,  but in this part of the world we have a very damp climate and it takes it toll on timber whether its exposed to the elements or not.
So if you want your cut roof to be around for the lifespan of the house its sat on TREAT IT!

Most wall plates I fit are treated (tanalised) but thats mainly because the timber merchants which supply 4x3 only supply it tanalised.

The rest of the roof is not tanalised and I think you'll find pretty much most of UK roofs are not tanalised your are among the minority then who thinks  they should be tanalised.    EVERY roof I have fitted and seen fitted and jobs i have been on for builders where they fitted the roof before I came to do my bit where untreated and have had work mates fit roofs who have never used tanalised timbers. I have been in the trade 7years and not seen or ever been told to use tanalised timbers for roofs.   Im sure Dean will agree he aint fitted a single tanalised roof.     A roof will NOT rot as long as it can breath and using tanalised timber will be just unnecessary extra costs.  

JMB

JMB

 

[jmbfestool]

1 problem with tanalised timber is all those popping screw head on the plasterboard because it is always soaking wet when it arrives. This is a warm roof so condensation will not be a problem.

Warm roof or cold roof  are both fine to use untreated timber.

JMB

 

[Wooden Lungs]

Tanalised or clear protim whichever suits you.....and yes I am in the minority that thinks the carpentry I do should be around for a long time after I am gone! I have only been cutting roofs for twenty three years JMB so sorry for being an amatuer.

 

[Wooden Lungs]

I admire the certainty you have that the roof will NOT rot JMB....LOL I have seen so many rotten rafters over the years that someone is obvioulsy doing something very wrong! only a while back we stripped a perfectly good roof (As far as the roof tiling and flashing was concerned) to find some serious decay and insect attack. The roof members were only installed around 1985. Think about it? if those timbers had been treated they would have stood a chance! We are using fast grown timbers that dont stand the test if time and they need a little TLC so drown them in chemicals ;D Warm roof / cold roof if left unmaintained or receives any damage to the tiles or fascia and soffit can 'F' up a roof. Anyway if you keep cutting roofs without treating them you will gurantee yourself work in the near future....so its gonna be a happy ending.

 

[Alan m]

iv never seen a treated roof  either.sometime parts are treated witgh green protim but never the the whole lot.
soulnds like a good jobexept for the environmental part on having all that arsenic  and coper cromate up there whating for you

 

[jmbfestool]

Tanalised or clear protim whichever suits you.....and yes I am in the minority that thinks the carpentry I do should be around for a long time after I am gone! I have only been cutting roofs for twenty three years JMB so sorry for being an amatuer.

Never said u was a Amateur at cutting roofs!  and I gotta admit I am one who often goes over board with things and I believe what your saying is one of those things.  

The roofs you have come across which are rotten/decayed is only because the roof was not maintained properly.  Broken tiles ripped felts.rotten felts leaking valley etc or not properly vented.     All these things should be repaired IMMEDIATELY  which will avoid any Rotting like I said.    

You can not be held responsible for home owners not looking after their property.    Just like you can not avoid rotting of your lovely set of windows and doors you made for a job cus the client doesn't bother maintaining them.     Maybe we should tanalise the windows and doors then just to make sure  [tongue]

JMB

 

[woodguy7]

I think the subject of ventilation is a good one.  I always make sure to have the specified ventilation done but I have lost count of the amount of home owners that have stuffed extra glass wool in the eaves because they think it is too "draughty" !

Home owners need to realise ventilation is there for a very good reason.  I'm not sure about other parts of the world but in the north of Scotland we always sheet the roof with sterling board or ply then felt.  There should be a 10 - 15 mm gap at the sheeting at the ridge & the felt cut the same.  This is to allow through ventilation, in at the facia & out at the ridge.  Constant flow of air.

Not sure but I believe south of the border you don't use any sheeting, felt over the rafters ?

 

[Deansocial]

yep felt over the rafters, i think the way you do it is better myself

 

[jmbfestool]

Alan!

Like Dean said Felt only no ply or sterling board used here.  

Dean!

Why do you think using ply prior using felt is better?!?!?! Just asking!  I have done it before but its rare!  I have nothing against it really just....

   Wouldnt this mean a lot more work for what benefits?! but also more work due to the need of counter battening cus if you didn't counter battern and water was to get behind the tiles the laths would trap the water between the ply and the lath.

JMB

 

[bellchippy]

    Wouldnt this mean a lot more work for what benefits?! but also more work due to the need of counter battening cus if you didn't counter battern and water was to get behind the tiles the laths would trap the water between the ply and the lath.

The reason that roofs are sheeted in Scotland is structural they get much stronger winds than we do in England.

 

[Deansocial]

like bell chippy says. this 1 moves about a bit more than i like but nothing i can do about it other than sheathing but builder dont want it so be it.

 

[woodguy7]

We also have to install wind bracing to the inside.  Diagonal & horizontal lengths of 100mm x 25mm treated overlapping at least 2 rafters or trusses.  Do you guys have to do that ?

 

[jmbfestool]

We also have to install wind bracing to the inside.  Diagonal & horizontal lengths of 100mm x 25mm treated overlapping at least 2 rafters or trusses.  Do you guys have to do that ?

On trusses we do not rafters.

JMB

 

[mattfc]

I think the subject of ventilation is a good one.  I always make sure to have the specified ventilation done but I have lost count of the amount of home owners that have stuffed extra glass wool in the eaves because they think it is too "draughty" !

Home owners need to realise ventilation is there for a very good reason. 

I would second that.. the mantra these days seems to be that you can never have enough insulation, so people are going crazy with polythene sheeting, duct tape, staple guns and wool etc to the detriment of circulation, causing lots of condensation problems

 

[Alan m]

when ever i insulate an attic i find the vents in the sofet and galvoband some 4"pipes (or what ever is on hand) from the soffet up over the insulation

 

[woodguy7]

The reason that roofs are sheeted in Scotland is structural they get much stronger winds than we do in England.
[/quote]

I will back this up by giving you an example of the winds here.  On Monday night the winds here were so bad my neighbours trampoline took flight & landed half on the roof of my van & half on my workshop roof  [crying]
To make matters worse I have to claim of MY van insurance  [mad]

Sorry, rant over.

 

[Alan m]

The reason that roofs are sheeted in Scotland is structural they get much stronger winds than we do in England.

would you notm clame off of their house insurance. they left the trampoline out in the wind and their trampoline damage your property

I will back this up by giving you an example of the winds here.  On Monday night the winds here were so bad my neighbours trampoline took flight & landed half on the roof of my van & half on my workshop roof  [crying]
To make matters worse I have to claim of MY van insurance  [mad]

Sorry, rant over.
[/quote]

 

[woodguy7]

Don't want to hijack this thread but to answer the question, their home insurance will cover their trampoline but none of my property !!!!!  I phoned my home insurance & they said that was right, they would say the same  [huh]

The only way is to claim off my own van insurance.  My no claims are protected but my premium will almost certainly go up in September.  Bloody maddening  [mad]

 

[Wooden Lungs]

The Arsenic in the old tanlith has been replaced with a water based AC500. So its not as noxcious. I still dont like cutting it but I suppose when we cut roofs its all outdoor work with the wind as dust extraction!
I by no means suggest that we all pour green tanlith all over our roofs! I always prefer clear. Most Truss roofs that we see erected on commercial and domestic jobs are pre treated in a pressure chamber, usually with protims or similar chemicals.

I would argue the point that most clients do not keep their roofs in good repair, so that's why I would choose a treated timber first for roofing. In the lifespan of a building it would have many occupants over the years and some may maintain the property whilst others may not.

I am definitely old school carpenter and I had it instilled in me to consider the work I do as having a long lifespan. Certainly some of the green oak projects I have worked on will last up to 1000 years. Given Oak structures are still standing in this country after being built 800 - 900 years ago. If you consider treatments that will come on the market over the coming years to preserve the work we do now and the work done many years ago by our predecessors. Check out 'Cressing Temple' to see an ancient timber structure! this all sounds fanciful but when I work I have in mind that some day some Carpenter will look at the work we are all doing now and think about how much effort we put into it, much the same as I wonder at the woodwork in the Tudor mansion we are working on now. My aim and the guys I work with is to preserve and restore work done by the Carpenters that came before.