moving stay lap in a post framed building

[dan moran]

hi all,
starting my first thread(i think).. im a carpenter from NW Indiana, 33 years old.. cant think of much else to introduce myself with.. hmmm- ok..
this site is an excellent source of info, and im really glad ive come across it.. so thanks in advance..

heres my question:

a friend of my dad's has asked me to build a storage loft inside their garage.. the building is post framed with trusses/ posts on 4 foot centers, with 10 foot walls.. what they want is a platform about 8' off the floor running the width of the building about 8-10' deep..

the problem is that the staylap (stiffback, ratrun, whatever) for the center chord of the trusses will create knee/hip high hurdle/tripping hazard/barrier after the platform will be built..

can i cut and raise the staylap about 5' without having structural problems with the trusses?

i only ask becasue i see a lot of threads about workshops etc and i think its a good probablity that someone has come across this situation in the past..

again, great forum, and thanks in advance...

[Joe Chritz]

Are these engineered trusses that are then attached to the posts or on top of a header?

If they are engineered trusses cutting any of the members without clearance from a structural engineer or the company that made them is asking for trouble.

If they are rafters then usually you can modify them as long as the loads continue to the posts unobstructed.

Joe

[David G Baker]

I am not a carpenter but I have done some reading about trusses. My understanding about a truss is that it functions very well as it is constructed and will carry a tremendous amount of weight until its structural integrity is violated. Once that happens the potential for a domino effect exists.
This is my opinion. I am sure someone else can add to this with more expertise and information.

[dan moran]

Are these engineered trusses that are then attached to the posts or on top of a header?

If they are engineered trusses cutting any of the members without clearance from a structural engineer or the company that made them is asking for trouble.

If they are rafters then usually you can modify them as long as the loads continue to the posts unobstructed.

Joe

thanks for replying,

its the staylap that ties the trusses together along the length of the building that i intend to modify. im not thinking of cutting any part of the trusses themselves, just the spreader/spacer that connects them in the middle.. i dont think that there are any bearing issues involved with these things(maybe side loading via wind against the gable end, but thats about it..)

what im looking to do is to have a 4' wide walkway between the trusses for the length of the span with headroom enough to maybe only have to duck down a little instead of making a high hurdle..

[dan moran]

I am not a carpenter but I have done some reading about trusses. My understanding about a truss is that it functions very well as it is constructed and will carry a tremendous amount of weight until its structural integrity is violated. Once that happens the potential for a domino effect exists.
This is my opinion. I am sure someone else can add to this with more expertise and information.


i am aware of the domino effect and i only asked the question because ive set trusses in a number of houses (only 24" centers though) and we were given a fair amount of leeway in where we were to put the stiffeners..

with the 48" centers im clueless though..

[Joe Chritz]

Can't really answer that one but I am assuming that by having a solid floor between the truss and the adjacent truss it would probably be fine.

I would add extra support up top and extend the support on the bottom an extra truss in both ways. That is a guess on my part from the same or less experience than you have so take it for what its worth. Attic trusses have large areas that are unsupported in the middle that way but they don't generally go to the sidewalls.

Maybe a call to a truss company could yield you some answers.

Joe

[Paul Simmel]

Dan,

IMO, it will depend on what your deck is made of.

As you know, on conventional 16” o/c or 24” o/c roofing, those stiffeners are primarily meant to hold the truss system (or stick rafters) together prior to sheathing. Once the sheathing is done, the OSB or plywood becomes the “stiffener”.

On your 48” o/c trusses, if your roof deck consists of thick timbers spanning the 48”, then IMO, you will be perfectly safe. If the truss system supports thin metal or the like, then IMO, you should continue to research… maybe erect some “W” members to restrict lateral movement.

Also, what’s to roof pitch?

[Rick Hutcheson]

If I understand what you are doing I think you are planning to hang this loft from the truss also. I would check with the company that built the truss. Mostly a truss is designed to carry the weight on the roof as per the code requirements for that area. Now you are going to hang a load off the bottom of the truss that it was not designed for. Plus the weight you will put on that loft has not been designed into the truss to carry that weight. I think you could be asking for a lot of problems depending on how the truss was designed to carry weight and where that weight was to be at on the truss, top or bottom.

[dan moran]

"If I understand what you are doing I think you are planning to hang this loft from the truss also."

no, im not. the platform will be posted up 8' from the floor(existing walls in the building are 10' tall or higher), with 2x10 joists and the only contact points with the building will be into the existing posts and their effective use is only inasmuch as they will keep the whole thing from falling down until i install the 3/4" sheathing,

im kinda thinking of this thing as a mostly-freestanding structure about 2' shorter than the existing walls.. i dont intend to put any loads on the trusses at all, im just thinking about a way to vertically displace the staylap (which is running perpendicular to the span) so as to remove any barriers to being able to walk the length of the span..

"Also, what’s to roof pitch?"
looks to be somewhere between 6-10/12 im guessing 8....


thanks for all the replies so far, i really appreciate them..
im thinking of giving a jingle to a truss company as i have an idea of what im going to do...

this kind of stuff is a whole lot easier thought about than explained..

again, cheers and thanks..