[Strawbale] Wall Capping

[Rene Dalmeijer]

Alex,

Besides slightly sloping the outside capping to allow water runoff. I would 
also do the following move the window out much closer to the exterior 
surface. This does 2 things it avoids possible moisture problems in an area 
that is difficult to inspect and it also improves the insulation value of 
the structure. There is less external surface working as a heat sink. This 
is a general rule for any type of building structure. The less the external 
exterior surface area for a given volume the more thermically efficient it 
will be. Another effect is that it lessens the effect of cold bridges which 
are always a potential problem around wall openings. Another effect which 
can be of some importance is that by reducing the external surface area 
maintenance is also reduced. There is less external surface area to deal 
with which requires the most maintenance.

The above again should also be considered in some balance because when 
pushed to an extreme moving the window flush to the outside surface or even 
projecting it out is not a good idea either. A window frame is quite a 
complicated (expensive) structure and also deserves some protection so it 
is a good idea to keep it back somewhat form the outside surface. In your 
case where you have big overhangs this is not such a necessity and you only 
need a small setback maybe about 100mm.

At 07:36 AM 2/1/04, you wrote:
>What I'm wondering is does anyone have any advice for capping the top of the
>wall ? Can I just use lime or would I be better with some other form of
>capping ? The plan is for the structure to look clean and smooth so I would
>like to avoid a heavy visible capping if at all possible. The window will be
>about 1m in depth. and the overhang about 2m.


Rene Dalmeijer