I have several locations in the house where I have a window, a foot of space above and then a clerestory all the way to the ceiling. The structural plan calls for an LVL beam but does not state if it should be below or above the clerestory. It would make sense to me that it would be above the clerestory to carry the trusses. This would, however, make the LVL beam stick above the double top plate on each side. Then likely the truss would need to be modified to have a notch that fits on the LVL beam or sits in a hanger. Is this a common scenario or am I misunderstanding something? Thank you.
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Sorry, not clear to me as to what you are describing. Maybe a quick sketch of your scenario or a pic of your blueprint would be helpful.
I have attached section from the plans demonstrating position of the LVL header with typical window placement. As mentioned, there are several locations in the house where there is also a clerestory 1 foot above this window. The overview plan calls for an LVL header in those locations but does not say where. If above the clerestory, wouldn't the LVL header then extend above the double plate. It seems that would look kind of "weird" an produce a "discontinuous" frame.I have reached out to the engineer but have heard nothing back and need to keep going. Thank you for your advice.
If I’m understanding correctly. You have a tall wall with windows at eye height, followed by a 1’ section of wall and a clerestory window all the way up from there? With the same width windows on top and below? Assuming this is the case, yes the header needs to go on top of upper windows to carry the ceiling/roof load. The area above lower windows may need a small header as well, just to carry the weight of the clerestory windows themselves (not enough info to call on that). If the wall has a pitched roof above with overhang, you may need a little space between clerestory (upper) windows and top plate for the overhang to clear the windows. Again don’t know the specifics of your project, but if you take a look at interior and exterior elevations it may indicate. For example if there’s an overhang the exterior elevation will probably show windows tight (or close) to the overhang, but the interior will show 1’ of wall above the window to the ceiling. If you do not have a pitched overhang and/or you have raised seat on your trusses the LVL might need to go on top of the wall. Again, not enough info to make the call. Whatever you do, make sure not to cut or alter the trusses as you will ruin them. Inspector and engineer will not approve cut or altered trusses. They can be altered in special situations, but engineers have to design the alteration and provide a stamp on that. Hope that helps some. Sorry need more info to make a better judgement.
I’ve had this situation before with clerestory windows above the header. We used structural mullions to provide the bearing between the plate and the header.
I’m going to ask a stupid question so please forgive me, is this detail in bearing walls? Are you sure it’s not in the gables? Like a trap window in an Adirondack?
Graceconstruction,
Thank you for your response. Yes, we have quite a few of these windows and they are in load bearing walls. The top of the clerestories is designed to be flush with the ceiling, which definitely does not leave sufficient space for a 7.25" header between the top of window and top plate. So is the answer to have a header sitting above the top plate or use a structural metal member, like an angle or channel iron here? Thank you again.
I don’t have the benefit of having your blueprint in front of me, so am making assumptions here. If there is a load bearing beam, girder truss etc above the plate line the truss manufacturer should have included that in the design packet, check there as well. If you are building in an area requiring building permit/inspection procedures your engineer (or in house engineer w/ truss manufacturer) will have to design or approve your design to pass. Truthfully, it should be shown somewhere on your blueprint or truss plan as I don’t know how the print examiner in your building department would have issued permit w/out seeing this info. Keep bugging your engineer. If he/she left that detail out they need to show you. Maybe they did include the detail, but you are missing it. Either way the engineer is responsible to help you out. Might need to be a little more firm in your approach with the engineer and tell him you contemplating legal considerations for time/$ lost from his/her lack of response.
jlyda,
Thank you for your time in trying to help me. We are building this house in the country and so no permits are required. I wish dealing with the engineer was easy, it is not, despite paying a lot of money...but I will not get into that.
I have attached 2 sections of a location that exemplifies the situation at hand. Window, clerestory above and trusses right above. I am the general contractor for this project and so have reviewed the plans hundreds of times in detail. There is nothing that deals with framing around windows/clerestories apart from the previously posted detail.
Thank you again.
From the exterior elevation (looking at window K) it shows about a 1’ of space above the window that has lap siding on it. This indicates to me that the header is installed tight to the underside of the top plate, not on top. Depending upon your roof pitch and trusses you may need to bring the header a bit lower than tight in order for roof eaves to clear the window. You will need to determine how low the overhang is before you decide where to place the header. Typically a standard 2x12 installed tight to underside of top plate leaves enough room for overhang to clear, but on occasion with steep pitches and large overhangs we need to sneak the header down a bit. Your interior elevation must not be matching the exterior elevation if they are indicating tight to the ceiling.
Also, for the windows below I would suggest a small header above those to take the weight of the windows above. They will not be taking much load, so a double 2x6 header should be fine (assuming window openings aren’t massively wide).
jlyda,
The space that you see is the face of the truss, please see attached. The drawing indicates TJIs but we will be using open web trusses. I don't think that should make a difference. Thank you again.
Okay, that’s not your typical overhang detail. Do you have a truss plan from truss provider? A standard truss will have a lot more shallow depth at eave of what is shown with the TJI. The truss will need to be designed to hang off a LVL above top plate if windows are tight to interior ceiling. A truss plan will (should indicate this). If you do not have a truss plan, your provider should supply one. You’ll have to metal strap the header to the top plate as well for uplift. If you have a standard truss not taking into account the raised LVL, you’ll need to sort that out with the engineer or truss manufacturer as to who made the goof. Or you have to install window lower than what you hoped to allow for LVL just below plate line.