Mono Pitch Roof Dilemma

Hi Guys and Gals,

Very soon i am building a single story extension at the back of my house, it will jointo an existing kitchen which has a mono-pitched roof, my questions are as follows;

1. Is there anyway without rebuilding both roofs to find the angle of the existing one so the new roof will match up with it ???

2. I am intending to screw a piece of 6"x2" to the back of the house then run 4"x2" rafters from it to the base plate on the new extension, will this be the best way to do it ???

Any help you could provide would be very much appreciated.

[quote="staningrimsby";p="864599"

1. Is there anyway without rebuilding both roofs to find the angle of the existing one so the new roof will match up with it ???

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there are several ways:
1. spirit level angle finder. 2. hand held angle finder. 3. expose the existing rafter, mark it with an upright pencil line (using a small level) then set a sliding bevel to the line. 4. remove the roof tiles and string a line.

2. I am intending to screw a piece of 6"x2" to the back of the house then run 4"x2" rafters from it to the base plate on the new extension, will this be the best way to do it ???

Click to expand...

sounds ok for a lean-to roof. rafter span will dictate timber section size. you will need to bolt the pitching plate to the wall. so long as the plate can accommodate the splayed cut then you will be ok. don't forget the ceiling joists and a pole plate for these.

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Thanks for the reply, didnt forget about the ceiling joists, but whats a pole plate ???

staningrimsby said:

Thanks for the reply, didnt forget about the ceiling joists, but whats a pole plate ???

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exactly the same as the pitching plate but lower.

there are wall plates, bearer plates, pole plates and pitching plates.

who knows

who cares!

so long as you describe what you are talking about with a degree of accuracy, then we will follow.

Now im really confused.

TonyB.(ex slater & Tiler/advanced craft/roofing lecturer/Chartered Surveyor/)Hi Stan-You can buy an angle finder from most good roofing merchants which is easy to use and will allow you to determine and copy roof pitch.Regarding 4 x 2 timber plate to structure to carry roof rafters,this seems fine,I would ask building merchants for correct expansion bolts /off hand I recall M8 check -and just take care not to overtighten bolts which will the crack bricks if overtightened.Bed wall plate and tie to main structure generally using galv. straps.The size of refters depends on length,obviously support half way would be required if the length and weight determined this.The scale can be advised by your building merchant.Joining onto anything normally is common sense,mono ridge are best fixed using a batton temporarily fixed to structure to keep tails of mono ridge straight whilt mortar sets.