Posted By: Don

I plan to replace all of the carpet on the second floor of my home with 3 1/4" x 3/4" solid strip flooring. Please refer to the attached photo. The hardwood will run parallel to the stair treads. There is a oak base at the bottom of the spindles which runs along the floor overlooking the stairs. Strictly by the book, I need to leave a 3/4" gap between the hardwood and the oak base in this location - but that would look like trash. What do you recommend in a situation like this?

Thanks in advance for your advice.

Don

I would ignore the expansion rule and install the flooring tight to that landing strip that the balusters are set in. That 3/4" expansion "rule" is overkill. No floor will expand that much except over a larger area or flooded. Another option would be to leave a gap and after the install is done, install a piece of molding on top of the floor to cover the gap. You could use a simple piece of thin flat stock or a fancy trim. I had to do this very thing last summer as the new landing strip wasn't wide enough to reach to the existing flooring. The solution? Installed a simple flat trim that spanned the gap.

Ken - Thank you for posting my question and attaching the photo on my behalf. Much appreciated!

Gary - Thank you for your quick response. I was thinking exactly the same thing. The landing strip is only about 3 feet away from the adjacent wall in the upstairs hallway where this is located so there is not much wood there to expand anyway.

Making a curved molding to fit around the radius of the landing strip is do-able, but not very easy to make, so I would prefer to avoid that option.

I was considering leaving 1/8" of expansion between the landing strip and the hardwood and caulking this with clear DAP Dynaflex 230.

However, my preference would be to fit the hardwood up tight against the landing strip and also leave about 1/2" expansion on the opposite wall (ie. undercut the drywall) if you think it will be OK.

Don

I agree lay it tight there

Art

This is just another example of why the 3/4 in space is a worthless recommendation. Shoot,butt both sides if you want. 3 feet of wood is not going anywhwere unless you flood it. Even if the room were thirty feet across,there would be no reason to back off from the stairnosing. Hell,its just another piece of oak among hundreds..

Who recommends that?

NOFMA: The Wood Flooring Manufacturers Association

The "old" rule of thumb was leave the expansion gap as thick as the wood you use i.e. 3/4" solid - leave 3/4"


The are only "general" guidelines and most professionals know changes they can make.

Art

I can see many DIY'ers getting into trouble with this thread. What happens when somebody installs some 3/4" hardwood(net fit against all walls/baseboard in a large area) with a low moisture content for example, and they live in the low areas of Louisiana? Suddenly it swells and whoa--trouble, trouble, and more trouble.

Small areas such as in the picture I see no problems with providing the hardwood has a place to expand on the opposing wall.

No they don't. They recommend a graduated expansion based on the width of the room. Something like a 1/32" per ft. Can't remember exactly and don't have the book handy but they do not say 3/4" for everything.

Ken - Thanks for your input.

Marco - Actually the NOFMA website and several other references that I have read including a hardwood installation book that I purchased by Don Bollinger all recommend 3/4" gap along the length and 1/4" gap on the ends of the boards. If you are interested, click on the NOFMA website reference below.

http://www.nofma.org/installation2.htm

Don

Well, I stand corrected. Have to dig up where I got the other number. I have worked for Bollinger as an apprentice and his shop manager and can tell you that is not his standard practice.

The whole expansion thing came about because someone thought that if an individual floor board (3/4" x 2&1/4") expanded by as little as 1/64 of an inch, then in a 12' wide room, the floor would expand by 1" total (2&1/4" times 64= 144"s divided by 12"= 12 ft.). The problem with this faulty reasoning is that they assumed that ALL the boards would expand at the same rate and we know that this is not true. A normal strip floor many have as much as 25% of rift/quarter sawn flooring mixed in that does not expand across the width the same as plain sawn does. It also assumes that all the boards will absorb the RH exactly the same; another faulty assumption. Furthermore, some fasteners (staples) prevent floor expansion (movement) better than other fasteners (typical cleats). Usually, when a wood floor is exposed to excessive humidity, it will expand against itself and appear to be "cupped" as the edges will be forced up from the pressure. This is termed "compression set" and will remain permanent if not remedied immediately. The wood fibers will be crushed at the edges and when the RH returns to normal, there will now be gaps in the floor as the flooring is now ever so sligthly narrower from the crushing forces of the expansion. Expansion at the edges of the install will not remedy this scenario. The exception to all this is a FLOATING FLOOR, which will expand as a single unit and does require the recommended expansion space. In conclusion, I have found that a 1/2" expansion space at the perimeter of a solid wood strip floor installation to be satisfactory in all situations and that one can routinely "net" cut the flooring to SOME of the fixtures (cabinets, nosings, etc.) in an installation.

Thanks,Gary.

You sure save me a lot of typing here. I could correct you in a few places,but I will simply defer.

CHU

Gary - Wow! Thanks for sharing that detailed explanation. It is clear that you have given this considerable thought and in my opinion, have responded quite intelligently. Very refreshing! I posted on this topic on another forum and was unable to get an intelligent response.

Personally, I could never understand how a hardwood floor could expand by 3/4" at the outer edges of the room if the hardwood flooring is actually nailed to the subfloor. If this were the case, the nails would be literally pulled right out of the subfloor.

Yet, everybody blindly quotes the 3/4" rule without challenging it. Even the manufacturer of the hardwood that I have purchased, Lauzon, writes this into their instuction booklet found in every box of hardwood. I can't understand why all of the literature prescribes to this, unless they are just trying to being conservative.

For a floating floor, multiplying the expansion of each board by the width of the floor makes sense to me completely, but for a nailed floor, I could never comprehend this type of logic.

Gary, your explanation is much more plausible - ie. localized cupping of the boards and compression set on the edges during high humidity, then gaps when the humidity recedes. From an engineering perspective (I am a mechanical engineer), intuitively that makes good sense.

The cleats are more forgiving - interesting! That too makes good sense to me as the board can slide up and down a bit on the cleat because the head is not that large, whereas the "U" shaped staple will tend to hold the tongue down more firmly.

If this is the case, and a "bit of give" is actually desireable, then what advantage do staples actually offer? Maybe they grab the subfloor better than cleats = good for OSB subfloors?

Marco - Neat! You actually apprenticed under Bollinger. Small world.

Don