[aldo_pearson]

This is driving me crazy so any advice is greatly appreciated!

An upstairs internal (non-load bearing) stud partition wall squeaks whenever I walk around on the floor near it. After a bit of investigation, I've found that there is a gap underneath the wall, i.e. between the wall and the floorboards, big enough to pass a pencil under from one room to the next. The squeak seems to be coming from the nails that hold the wall to the floor - it appears that the floor is flexing as I move around on it, and this is causing the squeak.

My question is - what can I do about it? On one side of the wall I've already taken the carpet up and replaced all nails in the floor with screws, but it seems the joists themselves may be flexing.

The squeak occurs when I walk on either side of the wall (one side is the landing, the other my bedroom, so it gets a lot of traffic!) and seems to be worse at some times than others.

Help!

[manhattan42]

The problem may actually result from a phenomenon known as "truss lift" if this partition is fastened to roof tusses above it.

Truss lift occurs as wood trusses flex up and down with seasonal changes in humidity.

When attached to the truss at the top, a partition wall can be pulled up as you see.

Nothing short of disconnecting the partition from the trusses in the attic will solve the problem permanently if in fact truss lift is the cause.

Here is a helpful link:

http://www.askthebuilder.com/B169_Re...s_Uplift.shtml

[aldo_pearson]

Thanks manhattan42, that does sound plausible.

We first noticed the squeak shortly after having the stairs and landing (including the wall in question) plastered, about 1 month ago - could the moisture given off as the plaster dried got into the trusses and caused this uplift? If so, will the trusses dry out over time and return the wall to its proper position? (And, if so, over how much time? )

[ballengerb1]

You could also consider inserting a shim in the gap, glued in place with construction adhesive. Your weight on the floor should depress the floor downward and the shim can be driven in to wedge it in place

[manhattan42]

If in fact the problem is caused by truss lift, the fact you noticed the gap only a month ago is probably coincidental to the plastering.

Truss lift generally occurs in warmer months as the absolute humidity of the outside air increases, and the wood which absorbs that moisture, expands.

Truss lift is therefore more likley to begin to occur in early spring and wane in fall in winter as absolute air humidity lowers.

(Warmer air carries more moisture than colder air.)

That said, the proper way to fix this truss lift problem is as explained in the link provided in my first post.

If truss lift really is the problem, bellengerb1's method will not solve the problem and could actually make matters worse.

The question you first need to answer is:

Do you have roof trusses and are these partitions nailed to them?

If so, truss lift is probably the cause of your raised partitions and squeaking floors and only separating the partitions from the trusses will solve the problem.

[aldo_pearson]

So, as I understand it, if truss lift is the problem then I should disconnect the partition fro mthe truss and re-attach it using L-Brackets which allow the truss to move up and down without lifting the wall.

If I do that, will the partition drop down onto the floor below (closing the gap)? And, if so, will I not create a big crack along the top of the partition, where it meets the ceiling?

[manhattan42]

So, as I understand it, if truss lift is the problem then I should disconnect the partition fro mthe truss and re-attach it using L-Brackets which allow the truss to move up and down without lifting the wall.

Correct.

If I do that, will the partition drop down onto the floor below (closing the gap)?

Correct.

And, if so, will I not create a big crack along the top of the partition, where it meets the ceiling?

Possibly.

When installing ceiling drywall where trusses are present, the drywall is normally not attached to the trusses within about 12" of the partion wall on all sides.

This allows the drywall to stay put and not move when the trusses go up and down, and prevents cracking at the top of the partitions.

Since you mentioned plaster in your original post, however, you may indeed get cracks developing at the ceiling-partition intersection as the trusses lift.

This can easily be remedied by installing crown molding at the top of the partition wall that is only fastened to the ceiling above.

This molding will then ride up and down as the trusses move up and down, keeping any cracks covered behind the molding and hidden from view.

[aldo_pearson]

Right, I've had a look in the loft and the house does have trusses, but the wall in question doesn't appear to be attached to them. The wall runs parallel to the trusses and about halfway in between two. It's not clear what the top of the wall is attached to as I can only see small sections in between lagging and lift flooring.

Does this rule out truss uplift? Or could there be horizontal pieces perpendicular to the trusses, but attached to them, which the wall in turn is attached to? I can't see any of these but, as I say, I can only see small sections at a time.

[manhattan42]

It is possible (or likely) that there are intermittantly space blocks of wood, fastened between trusses and to which the top of the partition wall is fastened.

You may have to remove insulation to see them.

If that is the case, then lift will still occur.

If the partions are not connected anywhere at the top, then we can rule out truss lift.

[thebigchap]

I had this exact problem and I am very happy to say it is now cured.

When I walked along the landing or in the bedrooms near to stud walls there was always a loud creak or crack. After adding extra screws to the flooring, wedges under the stud wall etc there was no improvement.

I fixed the problem by removing the skirting on one side of the wall. I sawed through the nails holding the wall in to the flooring. No more creaks.

I then screwed in 3 or 4 Timber-Tite screws along the bottom of the stud wall at 45 degrees ensuring they went into a joist below. My house is now silent under foot!
http://www.screwfix.com/p/timber-tite-joist-screws-6-5-x-100mm-pack-of-20/73190