The "run" on both these roofs please

[Chriswessex]

Evening all,

This is my first post so would be grateful for any replies.

My brother is building a porch and would like some advise on these to roofs please.

I posted two pictures of different hip roofs.

We would like to know if these roofs are set out differently, I.e is the run of one of these roof from side to side wall plate and the other run is just to the wall? Tad Hard to explain.

Thanks

 

[catlad]

I am not sure what you want but one of the porches is bigger than the other so the roofs will not look the same.

 

[Chriswessex]

Hi cat lad, yeh I noticed that, just using these pics as an example,

I wasn't sure if one was a lean to with hipped ends and the one is a hipped gable?

Meaning the hipped gable will always go to a point at the top

 

[^woody^]

A hip is at 45° on plan, so where it meets at the top depends on the width of the porch and how far out it is from the house

 

[noseall]

Give us the (plan) dim's and then we'll take a look. You would first need to consider the pitch in relation to what tiles you intend using and whether that pitch will interfere with any upstairs windows.
Below are three examples of the vagaries of hips depending on porch size etc.

Hippy

• noseall
• 5 Nov 2015

 

[Chriswessex]

Thank you so much for these comments!
Starting to make sense now.

The porch is going out 1.5 and 2.7 across.

We're going to use plain tiles but not sure weather to match the house which is 40 degrees or pitch 35 degrees (minimum tile pitch)

Thanks again!!

 

[Chriswessex]

Those were external measurements by the way, there is 100mm face brick and 100mm cavity to be deducted

 

[noseall]

If you were to pitch it at say 35 degrees (which looks fine without being overly steep) and were to include a 200mm soffit then your common rafter will be about 2136mm long.
However, you need to set your pattern rafter up on site. You need to decide on soffit overhang, b/m depth, rafter size (probs 100mm x 50mm) etc.

 

[Chriswessex]

Hi noseall thanks for that,

Would you mind telling me how you got that rafter length?

I got a different rafter length

Just realised I forgot to add the cavity and face brick, so total rafter I got is
1773

Cheers mate

 

[noseall]

Would you mind telling me how you got that rafter length?

Yeah I added too much or rather forgot to take off the cavity and the inner leaf dim's. Woops.
Try again....
You said your structure was 2700 long. I also suggested a 200mm soffit.
2700 divided by 2 gives you a run of 1350 plus another 200mm for the overhang gives a total run of 1550.
The trig gives a rafter length of 1892mm with a 35 degree pitch with a (horizontal) 200mm overhang. Soz for the confusion.

Hippy2

• noseall
• 6 Nov 2015

 

[Chriswessex]

Thanks noseall, really helpful mate,

I noticed you didn't deduct the 50mm ridge.

With the ridge deducted on those measurements the ridge should be 175mm?

Sound about right.

 

[Sonnypaul]

Evening noseall,

Our wee porch measurements have slightly changed.

wall plate dimensions are 2300 across and 1200 out.

still going for a hip roof but im driving myself mad on which way to measure my run etc.

top half of our house is tile hung so ideally we dont want a ridge.

would you please do me a sketch on how the rafters will look, especially the top peak.

were using bonnet hips as-well to match the house and i don't want the last two at the top so look odd, so i have to plead for your guidance.

yes i could get a chippie in but whats the fun in that aye!

Once i see how the rafters sit ill be on my way

 

[noseall]

With those dim's you won't end up with any ridge as such. Your two (short course) bonnets will touch at the top. Your two soaker cover flashings will also meet at the top. You will then make a lead cover apron that will deal with the tops of the eaves bonnets and the joint between the cover flashings which will dress onto and over the heads of the top two bonnets.
Simples.

Hipster

• noseall
• 15 Nov 2015

 

[Sonnypaul]

Wicked noseall thank you,

I know your sick and tired of me lol but what you sketched is what I couldn't understand, my run is 1150 from inside of rafter to the corner.

And then 1150 form corner to the centre of the middle rafter? The measurements wont be the same, I.e square

 

[Sonnypaul]

Pic