Double Roof

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Last post's picture
Double Roof
SoftPlan Version:
2016 Plus

I have a project where we're going to add some new roof joist on top of an existing roof 

so we can add some insulation.    The existing roof is the one of those Viceroy, Lindal,

Panabode style roofs with exposed beams and nominal 2" T&G Cedar that's left exposed

on the underside. So to add insulation we're building ontop of that.  Anyway my question

is; what would be the best way to place a double roof on a building for 3D purposes.

Certainly for 2D I could just line draw what I needed and I guess for 3D I could just make

the rafters quite deep and the fascia wide with a shadow board, but just wondered if there

was a way to actually do the double roof right off the top ?




Bill Wimberley
Bill Wimberley's picture
Double Roof

I would make a copy of the floor plan and call it ROOF2. Put your original roof on the original floor plan. Take the ROOF2 plan and erase everything but the bearing walls and beams. Convert all the walls & beams to plates 1 1/2" tall and offset 1 1/2" down. If the original house had multiple plate heights then make adjustments as necessary. Place your new roof on ROOF2. Stack ROOF2 on top of the original as if you were doing a 2 story house. The plates from ROOF2 would line up with the plates on the original and you would have your double roof. Don't forget to use a reference point on both drawings.

Bill is the owner and maintainer of

yvongonthier's picture
Double roof

Don't know if this is what you're looking for?


1- Draw your original roof with rafters

2- Copy just the roof over a set distance out of the way

3- Edit the 2nd roof; remove clean-up and reset your slopes

4- Move it back to its original position

5- While in section mode or 3D, adjust the heel heights and fascia depth of the 2nd roof

6- Turn off soffits of the 2nd roof

6- If you want to show the insulation, draw a ceiling, adjust slopes and height to be at or above the original roof decking and adjust height of your insulation.'s picture
Double Roof

Great, thanks guys will give those solutions a whirl.