roof decking

[michael lopiccolo(Guest)]

I am still in the planning stages,my idea is to use 2x6 t& g as roof decking,felt paper then shinges. Someone used T-11 as roof sheathing, so you get the look of T&G  between the rafters,and said , if the had to do it again they would of insulated and  install sheetrock or wood to the ceiling,
  I do not want to install rigid insulation then plywood, too expensive. My question is ,will the 2by hold some heat in?  I have a  wood stove for heat.
thank you

[RayN(Guest)]

Well I think one inch of wood = R 1.  I have a garage that the roof sheathing is 1x6 boards, pretty common in houses of a certain age in certain areas, it does look nice when you look up,  and the roofing nails don't poke thru.  You really need to sandwich something between the rafters to get some resistance to heat loss.  If you use OSB for the roof decking that would save you some money,  put up some insulation, and then use  sheetrock/paneling/T-111 on the inside.

[jraabe]

In the 1970's lots of cabins and second homes were built by companies such as Lindal Cedar homes. These used an exposed post and beam structure and then sheathed this with nice looking 2x6 T&G cedar on walls and ceiling.

Very handsome — they sold well and went up easy.

When the first energy spike hit in the late 70's and early 80's many of these cabin companies went out of business.

Except when built in Hawaii, or only used seasonally, these houses were all eventually skinned with foam insulation on the walls and ceilings. I helped my dad insulate his Lindal cabin. We put 1.5" of foam on the walls (inside) and 5" on the roof. It now is comfortable and has reasonable heating bills. Only the roof T&G is still exposed on the interior.

If you are building to code (whether or not it is to be inspected) you will want to do something similar in most climates.


Example of the breed...

[Hal Nash(Guest)]

How did you attach 5" of exterior foam insulation to the outside of the roof?

After doing that, how did you attach your roofing material over the 5" of foam insulation?

And finally, how did you cover the edges ... rake and gable... of the 5" of foam insulation?

I've looked high and low for how that's done ... never seen anything that comprehensively described this?

Thanks.

[jraabe]

If memory serves we discussed with the builder going with a full layout of 2x6 rafters (24" o/c) and rim boards that got infilled with foam (that would be 5.5" wouldn't it?) This was then skinned with sheathing. The rafters could be toenailled into the deck.

The other option was to wrap the roof with 2x6 cut down to the thickness of the foam and spike it all down using long screws and washers going through the sheathing and foam and into the 1.5" decking.

To tell the truth I don't remember exactly which way they did it. I do know it now has a nice fat roof! (Metal roofing went over the sheathing and replaced the old shake roofing.)