New extension roof

[Jsmithy]

Hi everyone,

I have built an extension and will be at wallplate next week, now my next job will be the roof construction,
the issue is that the extension roof has to match the existing roof at the back and then the ridge will be lower than the existing.
The front of the roof will then have to be a lower pitch than the rear? this is because the ridge due to matching the roof with the back will be off center over the new extension... i have mocked up a line drawing to show what i mean.

would this be a problem or is it ok to have one side at a different angle than the other?
any help advice will be apprieciated.
thanks
jsmithy.

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• Jsmithy
• 23 Jun 2013
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• Jsmithy
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• Jsmithy
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• Jsmithy
• 23 Jun 2013
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didnt mean to put 4 same pics up lol!

 

[Jackrae]

Hipped roof with an asymetrical centre might look like a dog's dinner.

 

[Jsmithy]

Yeah thats what i thought,
didnt even realise this was a problem until a couple of weeks ago.
when i got the steels in and started to bring the walls up i realised with the roof having to run in with the back and then meet the front of the extension there was an issue.
should have been thought of by the bloke who did my plans, but on those it all looks right but in reality.........

 

[Jsmithy]

The front of the existing house roof runs and stops at a small gable end.

 

[maltaron]

Why can't you continue the existing ridge, that would mean slightly longer jack rafters at one side and look much better. I think that the hip may be in twist if one side is longer than the other and it will be a pig of a job to have different cuts on each side of the rafter to hip joint.

 

[^woody^]

should have been thought of by the bloke who did my plans, but on those it all looks right but in reality.........

Have to gone back to him and asked him to sort out his mess?

If he has drawn the plans so that it looks right, then are the timber sizes now correct, and are all the bracing and supports adequate for a lopsided roof?

 

[Jsmithy]

Why can't you continue the existing ridge, that would mean slightly longer jack rafters at one side and look much better. I think that the hip may be in twist if one side is longer than the other and it will be a pig of a job to have different cuts on each side of the rafter to hip joint.

Yes that may be an option, but on the plan which was passed it shows the ridge being lower on the extension!
So i will ring the bloke who drew the plan and ask if moving it will be an issue.
Have you ever compensated for an issue like this before?
thanks

 

[Jsmithy]

should have been thought of by the bloke who did my plans, but on those it all looks right but in reality.........

Have to gone back to him and asked him to sort out his mess?

If he has drawn the plans so that it looks right, then are the timber sizes now correct, and are all the bracing and supports adequate for a lopsided roof?

Hi woody,
The plans didnt state anything other than the spars being 100 x 50 mm,
When i had the plans done and submitted i should have seen this problem as the extension is slightly wider than the main width of the house, and with the roof running into and matching at the rear and the ridge being lower then the new roof could not have ever matched the pitch at the back and front,
so therefore would have always had to have been a symetrical? does this sound right!?

 

[^woody^]

Here is what it will look like. The front lower pitch will be more noticeable by the time the tiles are on

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• ^woody^
• 23 Jun 2013
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If you can keep the ridge the same as the main house then that might be OK and not look too bad

But I assume that the ridge has been kept lower to conform to a planning policy? If so you would normally keep all pitches the same and hips at 45° and hide the difference with a gable or hipped gable.

If you move the extension ridge to the front and line it with the existing front gable ridge, then it looks like some thought has gone into it

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• ^woody^
• 23 Jun 2013
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[Jsmithy]

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• Jsmithy
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woody your rendering is better than mine
ive added the actual plans the front will be lower but if i can match the ridge then it wont look as bad as your image sugests? what do you think?
thanks.
edit The second renderind with the small hip at the back does look better,
although more work.
With a look a the plans do you think it would be do-able whilst looking asthetically 'ok' thanks again.

 

[tony1851]

OP; you can't do a hipped roof with the hips of different lengths. This
is because the rafters will then be at a different slope on each face, and it will cause you problems with lining up the fascia boards.

In plan, the hips should be at 45 degrees.

Woody's last sketch seems a logical solution.

 

[Jsmithy]

i agree woodys is a logical and good solution, only i was hoping i could get around this with a typical hip roof only with different degrees of fall on each side,
is it possible to make the soffits match by changing the gauge on the slates?
or am i clutching at straws!

 

[Jsmithy]

double post

 

[tony1851]

Were those plans drawn by an eleven-year old? The cross-section looks particularly amateurish.

 

[Jsmithy]

Were those plans drawn by an eleven-year old? The cross-section looks particularly amateurish.

no mate i seem to have been taken for a bit of a divvy,
the firm was nice to deal with and seemed very rpoffesional but mabye i should have asked more q's and made sure everything was done so it would work not just look like it would!