In New England many contractors strap out the ceilings for drywall. I now live in New York and am working for a Contractor who has never heard of such a thing. I am looking for more reasons for him to consider using strapping on the ceilings . Any suggestions.
Strapping the ceiling.
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If the roof is trusses on 24 inch centers, you generally strap to reduce the center to 16 inches for the drywall. Most trusses call for maximum unbraced bottom chord of around 10 feet. Unless additional bracing is added on top of the bottom chord, the strapping completes this requirement.
that is why you are to use 5/8 rock for 2 ft o/c trusses
All the framers I saw including myself were made to brace on top of the bottom chords for this ten foot rule. I highly doubt they strap these subdivision ceilings, never stuck around to find out.
I will strap a basement ceiling (joists) if it is an old house and they are wonky, and shim to flatten it out. It is a cheaper alternative to running 2x4's or 2x3's down the side of every joist. What Chris brought up though with fire having free reign in the joists does concern me though.
Strapping The Ceiling.
I was taught to brace the top of the bottom chord of the truss for structural reasons and to strap the bottom of the bottom chord for aesthetic reasons. I guess it's not unreasonable to skip the bracing above, though, assuming your strapping is decent stock.
But old habits die hard and lumber is cheap so I probably won't change anything anytime soon.
I was taught to brace the top of the bottom chord of the truss for structural reasons and to strap the bottom of the bottom chord for aesthetic reasons. I guess it's not unreasonable to skip the bracing above, though, assuming your strapping is decent stock.
But old habits die hard and lumber is cheap so I probably won't change anything anytime soon.
This is an interesting thread, sometimes an example of the trades following like sheep the guys before them without a clue why we do what we do.
When I framed and built in southern New England the only time I "strapped" a ceiling was to lower the ceiling elevation to accommodate the pitch of waste pipe in a long run. There it is called furring, I think the term is derived from the name given the metal product used in the same application. When I moved to NH I found everyone "strapped" all ceilings. When I asked my drywall guy why, he said "because everyone does". I asked him why as a drywaller he wants it, "because it isolates the movement between the cold ceiling framing and the warm wallboard". I continued with "OK, in a 2 story maybe that is needed on the second floor but why the basement and 1st floor ceilings? He thought for quite some time and responded "I guess there is no good reason". Some of the metal profiles have a single leg that allow for some float and lateral movement but wood is hammered home with 2 or 3 8Ds, how is that going to "give" ? And how is the movement in a cold ceiling assembly in NH different than the movement in a Minnesota ceiling (I'm guessing strapping is so popular there)- is ceiling cracking rampant there?
I've asked a few framers and got the "levels the ceiling" answer but nobody lines and shims so all that does is telegraph the highs and lows. I strap (fur) so I don't upset more people than I already have but I shim so the ceiling is flat. In some of the framing I did in SNE I would scope out the bottoms of the joists during the punchlist and rip straight the low hanging joists, take the rip and tack to high crowned joists.
I understand the idea that under trusses we are cutting the span of the DW from 24 to 16" but why when joists are 12, 13.2 or 16? Jeez, it just occurred to me we are INCREASING the span when we do it under 12" OC joists! And if the framing is wet/green I can see it but is it really needed if everything is KD?
As for a chase for wiring I thought if the cable is within 1 1/4" of the surface of the framing the NEC requires nail plates, kinda takes the savings away from boring joists, doesn't it?
A good point was made about flame spread, most codes address the max open areas in floor and ceiling assemblies, can't remember what the requirements are. In most cases the top plates block off the end cavity at each room and keep the areas small.
When I framed and built in southern New England the only time I "strapped" a ceiling was to lower the ceiling elevation to accommodate the pitch of waste pipe in a long run. There it is called furring, I think the term is derived from the name given the metal product used in the same application. When I moved to NH I found everyone "strapped" all ceilings. When I asked my drywall guy why, he said "because everyone does". I asked him why as a drywaller he wants it, "because it isolates the movement between the cold ceiling framing and the warm wallboard". I continued with "OK, in a 2 story maybe that is needed on the second floor but why the basement and 1st floor ceilings? He thought for quite some time and responded "I guess there is no good reason". Some of the metal profiles have a single leg that allow for some float and lateral movement but wood is hammered home with 2 or 3 8Ds, how is that going to "give" ? And how is the movement in a cold ceiling assembly in NH different than the movement in a Minnesota ceiling (I'm guessing strapping is so popular there)- is ceiling cracking rampant there?
I've asked a few framers and got the "levels the ceiling" answer but nobody lines and shims so all that does is telegraph the highs and lows. I strap (fur) so I don't upset more people than I already have but I shim so the ceiling is flat. In some of the framing I did in SNE I would scope out the bottoms of the joists during the punchlist and rip straight the low hanging joists, take the rip and tack to high crowned joists.
I understand the idea that under trusses we are cutting the span of the DW from 24 to 16" but why when joists are 12, 13.2 or 16? Jeez, it just occurred to me we are INCREASING the span when we do it under 12" OC joists! And if the framing is wet/green I can see it but is it really needed if everything is KD?
As for a chase for wiring I thought if the cable is within 1 1/4" of the surface of the framing the NEC requires nail plates, kinda takes the savings away from boring joists, doesn't it?
A good point was made about flame spread, most codes address the max open areas in floor and ceiling assemblies, can't remember what the requirements are. In most cases the top plates block off the end cavity at each room and keep the areas small.
And too many owners and GCs think labor is cheap also!
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I can picture an inspector saying "a random nail/screw can catch the cable that is within 1 1/4" of the backside of the wallboard" or "how does a trimmer putting up crown know where the strapping is". I know where you are coming from but I have witnessed inspectors drive electricians crazy with their interpretations of the NEC. Sometimes I feel sorry for you guys.
Jay, What I don't understand about strapping is how does strapping level (I'm defining this as creating a flat plane) a ceiling if it is nailed tight to every joist? A joist 1/4' low will push the strapping down 1/4" below the average plane of the ceiling, won't it? The only time I saw a framer flatten a ceiling with a high joist was simply not nail the 1x3 to that high joist so the strapping spanned 32"... in that case probably alright but what does he do if he has 2 high joists side by side or under 24" OC trusses- now he is spanning 4' or more?
I'm interested to hear how it makes it easier to hang drywall... not busting you, just trying to see it from your perspective.
For this conversation I'm looking at this from the practical standpoint- not how it is theoretically should be done but how really strapping is done the majority of the time.
I'm interested to hear how it makes it easier to hang drywall... not busting you, just trying to see it from your perspective.
For this conversation I'm looking at this from the practical standpoint- not how it is theoretically should be done but how really strapping is done the majority of the time.
ok,
I'll try to explain, how I think..
It doesn't level, makes all flat.
However in remodels like older homes.
You can actually shim the ceiling flat. this allows the crown molding and cabinets to fit better.
If you strap each room separately , perpendicularly from the outside wall
16" o.c.. when you hang the board it all fits less cutting. less ripping.
strapping is a 1x3 nailed to every joist or rafter.
the joist or rafter doesn't HAVE to be perfectly spaced or straight. the board hangs on the strapping.
sparky doesn't have to drill rafters or joist to run wires, the can run them in the space between the strapping.
HOPE THAT MADE SENSE, IF NOT ASK...
I'll try to explain, how I think..
It doesn't level, makes all flat.
However in remodels like older homes.
You can actually shim the ceiling flat. this allows the crown molding and cabinets to fit better.
If you strap each room separately , perpendicularly from the outside wall
16" o.c.. when you hang the board it all fits less cutting. less ripping.
strapping is a 1x3 nailed to every joist or rafter.
the joist or rafter doesn't HAVE to be perfectly spaced or straight. the board hangs on the strapping.
sparky doesn't have to drill rafters or joist to run wires, the can run them in the space between the strapping.
HOPE THAT MADE SENSE, IF NOT ASK...
Originally, strapping was a necessity. All the joists were either hand hewn or hand sawn, so you may have tree trunks with one flat face for the ceiling joists. Strapping just allowed the spots where the strapping would contact to be adzed out to get flat and level once they were in place instead of having to make 2 good faces and then having them sag once they were installed.
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Most of the houses we have built in the last few years don't have much drywall in them. I personally wouldn't put drywall on two foot centres even if it was 5/8. We don't strap main floors and basements that are already on 16 inch centres but we always strap the underside trusses. If the roof is hand framed on 16 inch we don't generally strap them. I am sure when people say it flattens the ceiling, they mean compared to just applying the drywall to two foot centres. Strapping does give you the ability to shim if required. The maximum unbraced bottom chord rules varies from truss to truss and is listed on the shop drawings for each truss.
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605 Posts
I was just going to say, although we don't strap ceilings, i can see why it would be beneficial under 24" trusses. The way trusses work to distribute deflective forces, I believe leaves a lot of room for movement. Strapping at 16" oc would further tie in the bottom cords an aid in reducing cracks and screw pops in the drywall.
Strpping the ceiling
After some research I have found several reasons for strapping the ceilings. Some are to give a higher quality to the building and some are to make the other trades jobs a little easier.
First, let's talk quality. Strapping helps to tie the whole building together. It helps to keep the joist from Rolling and popping screws in the drywall. It also to keep joint movement to a minimum, which leads to less cracking. You can use strapping to flatten the ceiling using shims. Strapping can also give more nailing room for the trim and can help keep your trim work tight. All of these thing can and will give you a better quality building.
Now let's talk about the other trades. Thee electricians can run their wire in the bays created by the strapping thus saving time by not having to drill so much. It ca also help in the mounting of lights and ceiling fan boxes. We all know less time = more money.
Plumbers can use strapping to run some of their lines in the bays and to support some of their drain lines. Again less time spent drilling and more money saved.
So all things considered I don't see much reason to not use strapping . If I want to produce a "Quality Building", and I do, I will use strapping on my ceilings.
As for cost, strapping is a drop in the bucket when you compare the gains you can get from using it. Plus the other trades will want to do more work for you because you have made their jobs easier.
After some research I have found several reasons for strapping the ceilings. Some are to give a higher quality to the building and some are to make the other trades jobs a little easier.
First, let's talk quality. Strapping helps to tie the whole building together. It helps to keep the joist from Rolling and popping screws in the drywall. It also to keep joint movement to a minimum, which leads to less cracking. You can use strapping to flatten the ceiling using shims. Strapping can also give more nailing room for the trim and can help keep your trim work tight. All of these thing can and will give you a better quality building.
Now let's talk about the other trades. Thee electricians can run their wire in the bays created by the strapping thus saving time by not having to drill so much. It ca also help in the mounting of lights and ceiling fan boxes. We all know less time = more money.
Plumbers can use strapping to run some of their lines in the bays and to support some of their drain lines. Again less time spent drilling and more money saved.
So all things considered I don't see much reason to not use strapping . If I want to produce a "Quality Building", and I do, I will use strapping on my ceilings.
As for cost, strapping is a drop in the bucket when you compare the gains you can get from using it. Plus the other trades will want to do more work for you because you have made their jobs easier.
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WHY?
Do you guys nail drywall or something? I personally would never nail a hanging job.
Have you ever had a sheet of 5/8" fall down?
Almost every house here is 24" oc trusses with 5/8" sheetrock. Have yet to hear of a sheet falling down. If you do manufacturer reccomended screw depth and spacing its fine.
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542 Posts
If I built subdivision houses, or in a commercial application I would consider using 5/8 drywall. I will not build anything on 2ft centres. All the houses we build have structural drawings done by an engineer. If he specs a roof section to be built on 24 inch centres I still frame them on 16 inch centre. Just me I guess but I build custom homes and feel that anything built on 24 inch centers except trusses are not custom quality. This is one reason we strap the underside of the trusses. No different than using thicker plywood on top of the trusses for extra strength. Doesn't mean lesser is totally evil, but building codes are the minimum, not the maximum.
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