Any roofers/joiners.

[Carl1974]

Sorry it’s not van related, I’m building a Pergola in the garden attached to the rear of the house. I have the wall plate and legs fitted, the joist that are from the wall plate to the end of the pergola how are the installed, do you need angle joist hangers or what is the best way.

 

[Ricardo T]

Joist hangers are not very pretty to look at and are not really designed to be seen so I would pre-drill the timber joists and screw from above on the outer plate and above and sides on the house wall plate using at least No10 size screws, say at least 50mm long and ideally stainless steel or exterior grade. Really the joists on the wall side want to sit ON the house wall plate (as they do on the outer plate), but if thats not possible 4 screws or so should hold it.Good luck!

 

[Carl1974]

Many thanks Ricardo, I was concerned that with the length being 3800 and using 4x2 it may need more than just screwing in. Every day is a school day. Many thanks.

 

[Chippie1]

As Ricardo said I would prefer the joists to be sat on the wall plate if possible

 

[Sawduststeve]

Hiya
How about a 2”x1” batton screwed along the bottom edge of the wall plate and notch your joists over it or sit them on it.
Good luck, you’ve made a good start.
Steve

 

[Paint]

If you have a multi tool you could cut notches out and do a halfing joint would be time consuming but a nice job us a sliding bevel to get the angle on the joists all the other idea will work but this would be the best way

 

[JOG]

If the wall plate unbolts, give some consideration to dropping it off again. (I know that's a ball-ache and I'm guessing you're doing the job on your own which makes it more challenging.)

By dropping it off the wall, you can "dry build" the roof on the ground doing the angles and notches you need. Then, when you get the wall plate back up, it will go together like Lego for you. You'll get to space your centres as you want them and deal with the soil/waste stack on the ground rather than working at a height. If you screw each joist from the top and the bottom along with a screw at an angle into each joist through the top of the wall plate, there's no need for ugly hangers.

Don't forget to run a silicone bead to seal where the wall plate meets the house (and a good dab on top of each screw you put in from above) as it is a moisture trap and could rot out the wall-plate more quickly.

 

[Carl1974]

Many thanks for all your replies and advice, I will try and look at removing the wall plate but as it’s 4800mm wide it was quite a task at getting it up there. Not sure if it makes a difference or a should have explained better on the initial post that the roof is sloped?

 

[Chippie1]

Many thanks for all your replies and advice, I will try and look at removing the wall plate but as it’s 4800mm wide it was quite a task at getting it up there. Not sure if it makes a difference or a should have explained better on the initial post that the roof is sloped?

It doesn’t matter that it’s sloped it’s just ideally you wouldn’t want to just screw in to wall plate attached to wall as it’s a fair bit of weight if it’s sat on the wall plate that takes all the weight of the rafters then the screws are just needed to hold in position rather than holding the weight of the rafter it’s self if that makes sense

 

[Carl1974]

Having been to the local roofing company and explained what I was doing I was given the extendable joist brackets. So three already up and the rest just waiting to be cut to size.

 

[Chris Sherwood]

As said above, the brackets will work but they are not pretty
You would be better off with a wood joint.

 

[Carl1974]

Just an update and more advice, since the structure is now up, what type of polycarbonate can I use, or what’s the best and strongest plastic to use. Don’t want the wavey plastic stuff, also can’t use glass due to its weight.

 

[dubber36]

Normally sheet material is supported on purlins as opposed to the rafters that you have. You'll need to join your sheets together along the length of the rafters, so you won't have a very wide bearing to fix onto.

 

[Sawduststeve]

Hi
Something like, rafter supported screw down Ali capping. The bottom gasket is 42mm. EBay.
Good work so far.

 

[david173]

We had the twinwall polycarbonate sheeting on a similar structure at my parents old house. Worked well and lasted a good 10 years till it started to look tired.

 

[Carl1974]

Just another with the slope.

 

[Sawduststeve]

Hi
Meant to add, either something like 6mm
Polycarbonate or acrylic. Can be bought in clear or obscure. Possibly a bit spendy now what with all the massive price increases of late.
Good luck

Steve