Detail Question - Blocking

[sbrown]

This is not a revit question persay, but more architectural/documentation in nature. What is the best way to show blocking and what type do you think works best. We have a detail with Metal Studs and a Metal Plate, but it seems quite wimpy when I see it installed in the field. We also use a detail with 2x8's and back to back studs. I've seen plywood screwed to studs too. Basically I want a detail that is easy to install but still gets me the support needed for wall mounted objects, ie casework, grab bars, etc. Or is the best practice to have various details for various conditions.

[jcoe]

We don't generally detail these conditions because of the work we do, but our specifications/ general notes call for 2x blocking in the wall cavity for items like casework, grab bars, door stops...

Some of our PM's have been accepting metal strapping in lieu of blocking, but my issue with this is that contractors are not using sheet metal screws to hang these items, they are using wood screws.

[gtarch]

My favorite is to use a metal stud, notched around the studs. Because it still has the C shape it's got rigidity.

And you can easily find different Sizes & Gages.

[Alex Page]

I worked on a multi-housing council project where in the bathrooms all the walls had plywood blocking under the finished lining. What this meant was in the future they could replace washhand basins, towel rails etc as part of there maintenance without worring about solid support and also if required could slap in some handrails/supports etc.

I thought this was a mighty good idea

[sbrown]

My favorite is to use a metal stud, notched around the studs. Because it still has the C shape it's got rigidity.

And you can easily find different Sizes & Gages.

We use this in Metal stud construction too. So for wood you would just switch to a 2x?

[gtarch]

We just have them use the metal stud blocking for wood or metal stud walls. It works fine for both. It's not hard to get metal studs, and it's not hard to find people who know how to work with them.

Like the other poster, when we have a real lot of things going on we'll put a layer of plywood under the gyp bd. And they can mount things to it any time, any place. We do this in labs, for example.

[cliff collins]

Depend on what is being supported.

Sometimes the building code also needs to be considered here.

If you are in a Construction Type which is non-combustible, there are certain requirements for allowing the use of combustible ( wood ) blocking--or it may need to be FRT wood, in which case we may specifiy metal
blocking, which could be either flat plate/sheet or stud work--depends on the loads that are to be supported.

We generally do not model the blocking, but we do use a "user-defined" keynote and may input the metadata into a Detail Component family for smart annotation and keynoting link to E-Specs for Revit, where the Specs call out specifics for blocking required behind various elements.

cheers

[patricks]

We use this in Metal stud construction too. So for wood you would just switch to a 2x?

Wood blocking in wood framing is usually just short pieces cut to fit between studs, and toenailed into place.

As far as I know, wood for blocking purposes is allowed and not required to be fire treated in Type I and Type II non-combustible construction, according to ICC building codes.

[sbrown]

Thanks to all. Does anyone know how much weight the wood blocking can support and the metal stud? I guess I could ask our structural engineer.

In Florida Building Code, Type II can have combustible blocking for handrails, cabinets, etc.

[Mike Sealander]

There are actually pull-out and shear values for a variety of fasteners that you might use to secure blocking to framing. In general, if you are installing a grab bar in a bathroom and need to have the grab bar be good for 200 pounds of force applied to it, four screws or nails between the blocking and the framing are probably OK. The problem in real life with wood framing is that toe-nailing is not an exact science. However, I think four fasteners per block (two on each side) will IN GENERAL get you to where you need to be.
At my old firm we actually had eight different blocking and backing details, depending on load. Not sure who did the math on all of them.

[kblaese]

I have seen a product in the field called Danback which is made by Dietrich Industries. Its basically plywood which is joined together with a sheet metal strap based on the spacing of your metal studs.

[RobG]

we deal with a lot of that in a typical detail that is put on the sheet with out typical partition types details.

[Revitman]

Hi Scott,

I vote for the variety of details to match up with the actual design condition. It is easy to say that a simple 2x8 blocking ran between the studs would handle most support issues, but we both know that this doesn't always do the trick.

Revitman- aAECs

[sbrown]

I'm planning on compiling a top 3 or 4 methods and typical installations.