To block or not to block. That is my question

[afinepoint]

I've got to do some siding work on the side of the shed where I tied the lean to rafters into the top plate.

I've been considering adding blocking at the mid point of the lean to's 11' rafters which are 2x6 pressure treated boards It wasn't required by code.

My concern was limited future movements.

Thoughts?

 

[cgrutt]

If it were mine I'd block it at midpoint and at end, assuming its open now (based on lighting in pic).

 

[tarmy]

The lower end is a must…they do work middle sorta depends on if you used longish screws for the plywood. If no…then block the middle too.

 

[Ultradog MN]

What do you expect the blocking to accomplish?

 

[afinepoint]

What do you expect the blocking to accomplish?

Halting or minimizing movements specifically twists.

 

[joe_pinehill1]

It can't hurt. Wouldn't it be called bridging?

 

[Ultradog MN]

It can't hurt. Wouldn't it be called bridging?

Hadn't heard of it called blocking. Might have heard bridging.
My thought was he wanted to do X bracing. Dont know if he needs it on a roof but agree it can't hurt.
I x braced the floor when I added onto our house. It prevents joists from warping and twisting and shares the load across 3 joists. Looks like they make metal ones now. I cut old fashioned 1x2s like shown.
... if that's what he's refeering to?

 

[Torque&Recoil]

I don't think it is necessary for this application. Not saying that blocking isn't important - it definitely can be. Let's consider what it accomplishes. Keeps rafters from twisting and buckling under load. The deeper the rafter, the more important it is to keep it vertical. The OP is using 2x6 material, which isn't going to move much. Also, the span is 11' and the load is only snow and rain. It's a lean-to ! I can't tell from the pic if there is a fascia board on the lower end, but if there is, that should take care of any possible buckling. Feel free to block if you want, but it's really not necessary in this application.

 

[afinepoint]

I don't think it is necessary for this application. Not saying that blocking isn't important - it definitely can be. Let's consider what it accomplishes. Keeps rafters from twisting and buckling under load. The deeper the rafter, the more important it is to keep it vertical. The OP is using 2x6 material, which isn't going to move much. Also, the span is 11' and the load is only snow and rain. It's a lean-to ! I can't tell from the pic if there is a fascia board on the lower end, but if there is, that should take care of any possible buckling. Feel free to block if you want, but it's really not necessary in this application.

No fascia. The tails are open.

 

[afinepoint]

Hadn't heard of it called blocking. Might have heard bridging.
My thought was he wanted to do X bracing. Dont know if he needs it on a roof but agree it can't hurt.
I x braced the floor when I added onto our house. It prevents joists from warping and twisting and shares the load across 3 joists. Looks like they make metal ones now. I cut old fashioned 1x2s like shown.
... if that's what he's refeering to?

No. Blocking. Not Bridging. Different animal. Blocking: Squared cut sections in this case of 2 x 6s slid between the rafters and fastened with 3" nails through the rafters and into the section's ends. Joists are also Blocked.

 

[NUTTSGT]

How old is this or built how long ago ? If it's recent, I would add blocking in the middle or two sets and divide in thirds. The way I have seen PT dry out and twist/warp, I would definitely add at least one row of blocking.

 

[afinepoint]

How old is this or built how long ago ? If it's recent, I would add blocking in the middle or two sets and divide in thirds. The way I have seen PT dry out and twist/warp, I would definitely add at least one row of blocking.

This summer.

 

[afinepoint]

Two more perspectives.

 

[NUTTSGT]

This summer.

I would get the blocking in before it dries too much and starts to twist and warp as it dries.

 

[NUTTSGT]

Two more perspectives.

What is keeping the birds out of the attic space now the soffit is open ?

 

[Ultradog MN]

Two more perspectives.

I say yeah block it.

 

[kmacht]

Why not just do it? It will cost almost nothing but a few pieces of wood and take very little time to install. Even if not needed, if you are questioning it just go do it rather than continue to overthink it.

 

[Ultradog MN]

By the way , We expect you to snap a chalk line and use a square to get every block perfectly in line and perpendicular to the sheathing.
We as a forum are going to stop by and inspect your work so no slouching. Okay?

 

[Whitworth]

11 feet ? It is not needed and it will look ridiculous unless it's done super neat.

 

[Hank11]

A plywood ceiling, some vents and a little creativity at the old and new rafter tails would make this lots nicer in every way. The plywood ceiling would negate any need for blocking.

 

[afinepoint]

It would have been so much easier to add prior to sheathing. Impatience has only downsides.

 

[Steve W.]

It wasn't required by code.

Please remember: "code" is only the MINIMUM that is required.

You are always welcome to do more (better) than that.

.

 

[Beauregard]

Blocking can easily be done from underneath. Find the center of the run, and snap a chalk line. Cut 2x6's and install with 16d nails, alternating each block on either side of the snap line.
Like this:

 

[nadogail]

vWhen in doubt, building it stout is generally less expensive than retrofitting any thing you did to what you considered “good enough” at the time.

 

[matt_i]

On one hand it could help to exclude birds. But it might be blocking a pathway to help ventilate the upper part of the roof where the lower is attaching.

Because the roof is already on, some of the nice sheet metal options are out. The 1x2s would be good but it's going to be tough to fasten with only a "x6" depth and it looks like 24"+ center spacing .

Blocking with some center holes sawed out would be good for airflow, wiring, and structure.

I would be quite particular about the fit, cut with a miter saw as if fitting stain grade trim. Improve the structure thru construction adhesive touching ends and top and by screws into the end grain, I'm a firm believer in the GRK- RSS for impressive holding power.