Possible volume problems by external wall thickness

cfbenson · Posts: 17

I've been playing around with the new ability to change wall thickness. While I profoundly appreciate having this new ability, I've noticed that it still does not seem to solve some of the problems I've experienced with previous versions.

For instance, if I'm simulating a straw bale home (with walls that are 2 ft thick) and am forced to create the building with several building blocks (because of its geometry) there appears to be a significant amount of lost internal volume. Now, even if this volume is being calculated correctly (which I could use assurance about), I lose the ability to control this shared space. If the volume is available, there is no way to assign it to either block or partition it between the two.

I've created a simple model very similar to one I've encountered in a real home. In this example the floor area (and presumably the associated internal volume) are dictated by the building block's wall thickness of the external walls. Even though these blocks share a wall, both sides of the shared space are reduced by the thickness of the corresponding building blocks - even though the wall itself is defined as a much smaller partition.

I've attached a small example. Here you can see that the smaller 10x10 block has an internal floor area of 36 ft^2. While this may make sense for the upper portion of the block (structural arguments aside), one of the walls is shared for the bottom. I am under the impression that what should be considered open space (a 4x6x8 ft portion or 192 ft^3) is not accounted for.

Can someone please tell me...

1) Is this volume being accounted for.

and

2) If so, is there a way to partition or assign that volume to either of the zones?

Thanks
- Chris

Andy Tindale · Posts: 2432 Location: Stroud

Chris,

You can control the way DB calculates the volume of zones with interblock connections by selecting the 'Generate enclosed zones' advanced model option.

This has 2 main effects on the model:

1. Extra Link surfaces are generated to connect adjacent blocks together for both visual continuity and to allow fully closed zones to be generated.

2. The volume enclosed by the link surfaces and the inter-block partition is included in the zone volume. This volume is essentially the thickness of the block wall x inter-block partition area).

For more on these surfaces see:

http://www.designbuilder.co.uk/programhelp/surface_types.htm

Please see if this explains it and report back.

Andy

cfbenson · Posts: 17

So if I want to have these two joining blocks previously mentioned as separate zones (with an internal partition between), does DB automatically split the volume between the two zones? Is there a way to control how much will be given to each zone?

Similarly, when defining wall thicknesses, is this also controlling the thickness of the roof? If so, is there a way to separate the two and independantly change the thickness of the roof.

- Chris

Andy Tindale · Posts: 2432 Location: Stroud

The amount of volume given to each of the 2 zones is determined by the wall thickness of the block - so the only way to control it is to change the block wall thickness.

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