Deck Head Insulation Again....Sorry Folks

[The Grumpy Triker]

Hi there,

 

I know there have been loads of threads on this but I need to ask a more specific question please?

I have used Thinsulate in between the deck head ribs and was then going to roll out a vapour barrier secured in place with the battens I need for the deck head choice....undecided as yet.

 

Then I read again and everyone states that no metal should be left uninsulated....given this, should I lay out a thin product like Airtech double foil to cover over the deck head ribs, cover this in vapour barrier and secure in place with battens?

 

  -  In addition, where I screw the battens in place through the vapour barrier & insulation, should I use a sealant?

 

Sorry folks and I know a few of you will be rolling their eyes but It's been a while as I have not been completing the jobs as planned due to other issues.

 

Cheers all ?

[Tony Brooks]

FWIW When I redid the back cabin I left the original polystyrene insulation in place and then stapled aluminiumised "bubble wrap" over insulation and battens. Then I fixed the decorative deck head through the bubble wrap. no signs of water or damp yet after about 12 or 14 years.

[smileypete]

I'd not have interior ply or a vapour barrier up against bare steel ribs, best to have batten in between, as Tony describes. The vapour barrier should go on the warmer side.

 

Also the foil stuff works somewhat well enough as insulation if there's a decent air gap on at least one side, even 1" will do OK, though don't worry if the other insulation is too thick to allow this. Maybe worth a look at graded roofing batten and self drilling countersunk head 'tek' screws.

Edited June 3, 2018 by smileypete

[The Bearwood Boster]

I did not read that as Deck head, should have gone to Specsavers...?

[Tony Brooks]

31 minutes ago, The Bearwood Boster said:

I did not read that as Deck head, should have gone to Specsavers...?

That's the trouble when people use the nautical term.

[The Grumpy Triker]

55 minutes ago, Tony Brooks said:

That's the trouble when people use the nautical term.

I was told never use a Scouse accent when using the term - it took me a few minutes as it was late night when I read it ?

1 hour ago, smileypete said:

I'd not have interior ply or a vapour barrier up against bare steel ribs, best to have batten in between, as Tony describes. The vapour barrier should go on the warmer side.

 

Also the foil stuff works somewhat well enough as insulation if there's a decent air gap on at least one side, even 1" will do OK, though don't worry if the other insulation is too thick to allow this. Maybe worth a look at graded roofing batten and self drilling countersunk head 'tek' screws.

Oh OK - not sure why but I thought it was batten outside ...doh! .....what about the exposed steel ribs?....put an insulation layer between the batten & the steel?

[The Grumpy Triker]

3 hours ago, Tony Brooks said:

FWIW When I redid the back cabin I left the original polystyrene insulation in place and then stapled aluminiumised "bubble wrap" over insulation and battens. Then I fixed the decorative deck head through the bubble wrap. no signs of water or damp yet after about 12 or 14 years.

Wish I'd had that option ? all a bit in need of 'rip it out & start again' mode....everything up high was rotten, sodden or grotsville.

 

Good tip though ?

[Tony Brooks]

41 minutes ago, The Grumpy Triker said:

I was told never use a Scouse accent when using the term - it took me a few minutes as it was late night when I read it ?

Oh OK - not sure why but I thought it was batten outside ...doh! .....what about the exposed steel ribs?....put an insulation layer between the batten & the steel?

If you want to. Once you keep water vapour away from the cold steel there should be little condensation forming on the steel. I think I would give all the steel several coats of paint and then something like I used or a veneer of a closed cell insulation.

[The Grumpy Triker]

10 minutes ago, Tony Brooks said:

If you want to. Once you keep water vapour away from the cold steel there should be little condensation forming on the steel. I think I would give all the steel several coats of paint and then something like I used or a veneer of a closed cell insulation.

Cheers Tony, have to admit I did repaint the deck head steel with several good coats of Hammerite but had got my layers all wrong it seems ?

...as per your hint I want to do a decent job that lasts at least 2yrs?

 

Cheers again for that.

 

[smileypete]

1 hour ago, The Grumpy Triker said:

I was told never use a Scouse accent when using the term - it took me a few minutes as it was late night when I read it ?

Oh OK - not sure why but I thought it was batten outside ...doh! .....what about the exposed steel ribs?....put an insulation layer between the batten & the steel?

Where the ribs are the order would be: cabin roof/sides -> ribs -> batten -> vapour barrier -> lining plywood

 

In the span between parallel ribs the order would be: cabin/roof -> thick insulation -> vapour barrier -> lining plywood

 

Thick insulation can be up to the combined depth of the ribs and batten.

 

Sometimes the vapour barrier incorporates a layer of thinner insulation, in the case of the foil bubblewap. This will end up getting sandwiched between batten and lining ply, but that's OK.

 

Clear as mud?

 

 

[The Grumpy Triker]

14 hours ago, smileypete said:

Where the ribs are the order would be: cabin roof/sides -> ribs -> batten -> vapour barrier -> lining plywood

 

In the span between parallel ribs the order would be: cabin/roof -> thick insulation -> vapour barrier -> lining plywood

 

Thick insulation can be up to the combined depth of the ribs and batten.

 

Sometimes the vapour barrier incorporates a layer of thinner insulation, in the case of the foil bubblewap. This will end up getting sandwiched between batten and lining ply, but that's OK.

 

Clear as mud?

 

 

?

Great stuff thanks for this, thought I'd have to add a layer of insulation over the ribs ?

[WotEver]

17 minutes ago, The Grumpy Triker said:

?

Great stuff thanks for this, thought I'd have to add a layer of insulation over the ribs ?

The wooden batten works as the insulation at those points. 

[The Grumpy Triker]

25 minutes ago, WotEver said:

The wooden batten works as the insulation at those points. 

 

25 minutes ago, WotEver said:

The wooden batten works as the insulation at those points. 

 

25 minutes ago, WotEver said:

The wooden batten works as the insulation at those points. 

? Happy Days....and glad I asked else would have had it wrong way round.

 

Not cut and installed my stove flu as yet, still unsure what insulation to use around that and for how far I need it - will be a twin walled flu...any recommendations - guessing I have to leave the statutory 3/4 flu width before the thinsulate at least...do I fill the area immediately around the flu with rockwool

[Tony Brooks]

36 minutes ago, The Grumpy Triker said:

 

 

? Happy Days....and glad I asked else would have had it wrong way round.

 

Not cut and installed my stove flu as yet, still unsure what insulation to use around that and for how far I need it - will be a twin walled flu...any recommendations - guessing I have to leave the statutory 3/4 flu width before the thinsulate at least...do I fill the area immediately around the flu with rockwool

That is what I used for about 6" between flue and wooden frame that located the polystyrene insulation. Then in filled with rock wool. I fitted a down-stand of decorative timber at the surround battens for the decorative deck head to but against. I covered the rock wool with fire board painted with black stove paint.

[The Grumpy Triker]

2 minutes ago, Tony Brooks said:

That is what I used for about 6" between flue and wooden frame that located the polystyrene insulation. Then in filled with rock wool. I fitted a down-stand of decorative timber at the surround battens for the decorative deck head to but against. I covered the rock wool with fire board painted with black stove paint.

Great idea on the fireboard... cheers again Tony.