Insulating a home office

Happyman42

Building a home office/spare room in the garden. It is a timber frame construction.
Will placing more insulation underneath outside cladding be overkill, will it serve any purpose?

Carlow52

your proposal is counter productive

have a look here:
http://www.boards.ie/vbulletin/showthread.php?threadid=2056082161

If u build this the wrong way from a water vapour permeability/ dew point line perspective the timber structure will rot in jig time

Happyman42

Thanks for having a look Carlow. Would you have or know where to get a drawing of how it should be done, not really getting all the technical lingo.

Carlow52

Try any of the TF housing website/ ask for brochures.

The C and P section here might have some details

Dont mind the lingo, the issue is quite simple really once u know who the enemy is.

The enemy is warm,water vapour laden air from the inside that tries to get out through the wall/roof/floor and as it does it cools.
As it cools, its ability to hold the water vapour reduces and eventually it reaches the dew point temp which is where the water vapour condenses out as water.

You dont want that happening in ur insulation inside an impermeable membrane.

So the inside of the building should have an airtight membrane (ATM) fully sealed around doors windows roof floor.

In the link I posted u will see a service cavity, this is inside the ATM so no holes in the ATM for cables sockets pipes etc.

You then have ur insulation/frame and on the very outside a breathable membrane such as the tyveck u mentioned..

I would use breathable insulation as opposed to the foil back rigid stuff.