# Raising collar ties



## Scuba_Dave (Jan 16, 2009)

Do you have a picture?
They may be rafter ties - which keep the walls from bowing out


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## Anne (Aug 9, 2008)

Does this help?


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## Scuba_Dave (Jan 16, 2009)

Collar ties are installed in the top 1/3 of the rafter
If your Cape is like mine the roof rafters are attached at the floor to the ceiling/wall below?

My collar ties were installed within 12" of the peak for more headroom


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## stuart45 (Jun 20, 2009)

I would check with a Structural Engineer before you make any alterations to your roof structure. The Building Regs in my area state that collars should be no higher than 1/3 of the height of the roof from wall plate to ridge. The higher the collar is the less effective it is against roof spread. These regs only apply if the attic is half in the roof space and the rafter feet are not joined by ceiling joists. The idea of the collar roof is to allow some of the room to be in the roof space, saving brickwork as the walls can be lower. It will also depend on the weight of your roof covering and the loads likely to be imposed by wind and snow. I have known people to change their roof covering from slate to concrete tiles and the extra weight has caused the roof to spread and push out the external brickwork.


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## Scuba_Dave (Jan 16, 2009)

If as stated this is a Cape house then the 1st floor ceiling joists hold the rafters together
If you have knee walls/walls above what is shown front & back of this picture then the rafters could spread

A picture of the outside roof plus a bigger picture that shows both ends of the collar tie would help


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## Anne (Aug 9, 2008)

Thanks for your replies so far. I'll take some better pictures, including one of the outside of the house this evening and post them.


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## tinner666 (Mar 14, 2005)

Per the advice we got from a building inspector on a similar project. We had to cut sheets of plywood to 14" wide, by 4-5' long, at the point. We decided the ceiling height, then put the plywood on the rafters, opposite where we were relocating the raised collar ties/ceiling joists.

You may have to ask your building dept. or an engineer if this is a suitable alternative.


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## stuart45 (Jun 20, 2009)

Sounds like a good idea.


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## Anne (Aug 9, 2008)

Here are some more pics. The first one is the exterior. The area in question is the peak that runs from front to back of the house.

The second is a larger picture of the exterior and the third is my attempt at giving you a closer look at the rafters.

Hope this helps a little more.


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## stuart45 (Jun 20, 2009)

Anne,
It looks to me from the new photos that the rafter feet are tied by the ceiling joists and not by the collars alone. It might be worth getting a carpenter to have a quick look on site before you start work, as it's hard to be 100% sure from photos.


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## philS (Jul 10, 2007)

I've done this on two houses and in both cases the building department required an engineering analysis. Even if it's not required, it's not a big expense, and could save you huge amounts of money down the road.


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