James:

I've never seen bookcases that need to be anchored to the floor, but presuming
that that is in fact the case, the answer is simple:

Presuming we are looking at the cross-grain wall where there will be significant
expansion and contraction, remove a nice long slot before and behind the bolt-
hole so that there is room for the floor to expand and contract without the bolt
interfering.

I'd be inclined to look for two shims of a reasonably slippery material that I
could put under the bookcase to increase the ability of the floor to move
despite the bolted-down and heavy bookcases.  Maybe just a pair of stainless
steel plates?  I don't know if it is necessary but. . . .

Micah

-----Original Message-----
From: oldtools@g...  On Behalf Of James DuPrie via groups.io
Sent: Tuesday, January 4, 2022 6:42 AM
To: Tools Old 
Subject: Re: [oldtools] wood movement and construction question...

A clarification:
My concern with the shelves over the floor is that, because the shelves need to
be secured to the floor every 38", that they would cause problems with floor
being able to move as it expands/shrinks. The design of the shelves is to have
freestanding sides, anchored at top, bottom, and back.
The shelves are adjustable, so offer no structural integrity.
Of course, that means that if the sides are secured through the hardwood
flooring to the subfloor, there would be an immovable point every 38".....
If I install the floor under, and do it during the most humid time of year, I
guess the issue would go away, as all there would be is shrinkage.....

From what people have said (thanks!) 1/2" of expansion space on each end would
allow for any expansion across the whole floor, so if I did the floor after the
shelves, all I have to do is include some baseboard molding.....

thanks again....

-James

On Mon, Jan 3, 2022 at 8:09 AM James DuPrie via groups.io  wrote:

> I'm moving forward on the library project (year 2 now), and I figured 
> I'd toss the latest dilemma to the porch....
>
> The library is an unfinished room, 28' square. I'm pondering order of 
> operations. The shelves will be built-in on all 4 walls.
>
> the question is: should I put the floor (probably maple) in first, and 
> build the shelves on top of it, or build the shelves first, and butt 
> the floor against them?
>
> The shelves will be secured to the floor (roughly every 38"), and I am 
> a bit concerned with restricting cross grain wood movement if I put 
> the floor in first. However, most of the places where I've seen 
> built-ins, they are built over an installed floor.
>
> I'd actually prefer to put the floor in last, so I don't have to worry 
> about scratches, gouges, and such but then, with a span of about 26' 
> I'm worried about expansion and movement. With a span that big, will 
> the floor trim be enough to hid any movement? We don't use A/C, and we 
> heat with wood in the winter, so humidity levels range from 95+% in 
> summer to 35%-40%  in winter. I've had no problem designing furniture 
> to allow for that, but I've never done a floor...
>
> Am I being overly paranoid?
>
> thanks
> -j
>
>
> 
>
>
>