Floor sagging under whole house fan install location (and floors below those)
#1
03-11-13, 07:11 PM
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Floor sagging under whole house fan install location (and floors below those)
The floors in the house have always felt funny but now 2+2=4. I was hanging doors this weekend into a house we bought less than two months ago (2 story w/ basement). Only one door was not square in it's framing. When closed the variance between carpet to door is 1/2" in one corner and 1 1/8" in the other. I looked up and sure enough this door is right under the whole house fan. I went into the attic and couldn't find any semblance of having "shored up" the trusses prior to cutting them. So this also perhaps explains the cracks at the bottom of the stairs (both 1st to 2nd floor and basement stairs).
What can I do? The fan is pretty old so I'm guessing it's a decade old or so. A new roof went on two years ago. I'm fantastically handy and can think of some solutions to start jacking it up that 5/8" from the basement to the 1st, then 1st to 2nd and 2nd to attic. But would then straightening/strengthening the attic trusses after all that prevent the resinking of the house?
Please let me know what other info you need or pictures. The more specific you are the better I can take them.
Thank you.
What can I do? The fan is pretty old so I'm guessing it's a decade old or so. A new roof went on two years ago. I'm fantastically handy and can think of some solutions to start jacking it up that 5/8" from the basement to the 1st, then 1st to 2nd and 2nd to attic. But would then straightening/strengthening the attic trusses after all that prevent the resinking of the house?
Please let me know what other info you need or pictures. The more specific you are the better I can take them.
Thank you.
#2
03-11-13, 07:19 PM
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Problems don't start from the top of a house and go down... they start at the bottom of the house and go up.
You are correct in thinking you need to start in the basement, but we have no information to start with. For us to give you some decent advice, we'd need to know the structure of the basement, where beams are located, orientation of floor joists and so on. Pictures would be worth 1000 words.
Also, you can't usually just go jacking a house up, as it will usually produce all sorts of cracks in the drywall and plaster... plus point jacking is not always the way to get results. You often need support beams in place so that you are raising entire areas, not just one point of the house.
You are correct in thinking you need to start in the basement, but we have no information to start with. For us to give you some decent advice, we'd need to know the structure of the basement, where beams are located, orientation of floor joists and so on. Pictures would be worth 1000 words.
Also, you can't usually just go jacking a house up, as it will usually produce all sorts of cracks in the drywall and plaster... plus point jacking is not always the way to get results. You often need support beams in place so that you are raising entire areas, not just one point of the house.
#3
03-11-13, 07:58 PM
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The basement to 1st floor and 1st to 2nd floor joist are 24" on center runs of some sort of 2x4 and metal plate (pictured). Attic trusses are 2x4 and also 24" om center. House width is 26' and the basement joist span the whole shebang for about one third of the length. (40'). Pictures are labeled. The only other notes I'd add are the WHF is to the left of the door 1' and I've noted the crack in upper corner of the door (what is used to look like) and it is also mirrored on the back side. Joists are perpendicular to that door. The stairs are just to the right of that door. They had a crack that was similar but maybe not as severe as the basement one (pictured).
Let me know you other questions and specific pictures.
Let me know you other questions and specific pictures.
#4
03-11-13, 08:42 PM
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That's a good start. So can you give us a better shot of the basement web trusses? Especially a well lit picture of the metal bracket and vertical web support? Also the depth of that web truss in inches (hope they are about 24"). Are there any permanent mfg tags on them that might i.d the mfg or tell us a little bit about them?
Do the basement web trusses span the full 26' below the area where this cracking is occurring... below the WHF? I assume the web trusses in the basement are parallel with the roof trusses?
You say the basement web trusses span the 26' width of the house for roughly 1/3 of the 40' length of the house. Can you describe the location of bearing walls in the other 2/3... and do they line up under vertical webs of the web trusses? Also are there any horizontal strongback 2x6's running through the web trusses, tying some of the vertical webs of each truss together? (these important locations are engineered and are usually clearly marked on the trusses)
And are the cracks showing up mostly in the 1/3 of the house (as mentioned above) or do they also show up in the other 2/3?
Finally, up in the attic, are those really trusses... with steel mending plates where the web members come together? Just making sure. Trusses should never be cut (as in your whole house fan) and if they are, that usually needs to be engineered/okayed by the truss mfg.
Just trying to get a better picture of what's going on and why.
Do the basement web trusses span the full 26' below the area where this cracking is occurring... below the WHF? I assume the web trusses in the basement are parallel with the roof trusses?
You say the basement web trusses span the 26' width of the house for roughly 1/3 of the 40' length of the house. Can you describe the location of bearing walls in the other 2/3... and do they line up under vertical webs of the web trusses? Also are there any horizontal strongback 2x6's running through the web trusses, tying some of the vertical webs of each truss together? (these important locations are engineered and are usually clearly marked on the trusses)
And are the cracks showing up mostly in the 1/3 of the house (as mentioned above) or do they also show up in the other 2/3?
Finally, up in the attic, are those really trusses... with steel mending plates where the web members come together? Just making sure. Trusses should never be cut (as in your whole house fan) and if they are, that usually needs to be engineered/okayed by the truss mfg.
Just trying to get a better picture of what's going on and why.
#6
05-29-13, 02:39 PM
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Hi XSleeper - I owe you an apology! I'm sincerely sorry I've just left this hanging.
So... I've finally been poking around and sure enough the attic joists were NOT cut. I brought over my uncle-in-law who's an engineer and he deduced that you are correct, something is amiss in the basement. Sadly I won't find out for a bit since it's all drywalled and I'm not going to tackle that for months. Consider this a cold case for now and I really appreciate you pitching in so quickly.
My very best!
So... I've finally been poking around and sure enough the attic joists were NOT cut. I brought over my uncle-in-law who's an engineer and he deduced that you are correct, something is amiss in the basement. Sadly I won't find out for a bit since it's all drywalled and I'm not going to tackle that for months. Consider this a cold case for now and I really appreciate you pitching in so quickly.
My very best!
