Was reading the Brazilian Cherry Gapping thread and have a question.

[fixitpete]

This might be a newbie question... but here goes.

In the past I've done T&G beadboard ceilings... and if I do them in the summer months, come winter you see more of the tongue as they contract from less humidity and cooler temps.

With that being said:

What the heck happens if you do the opposite (in this case with flooring)? You install in the WINTER -- what the heck happens in the summer months? Yikes? Buckling?

I understand making sure you get the tolerances between subfloor and materials to proper % re: moisture... but can you still get buckling?

Confused,
Pete

[Cdat]

Yes. If no expansion joint and the wood is dry in the winter, it'll buckle.

[fixitpete]

Understood.

In a small room, say 10x10, the expansion joint is simply the space left around the perimeter of the room, correct?

With that being said, and floor being made up of many boards (in my case 3.25") why would the the planks not buckle at the T&G?

(Just like you would see gaps @ the T&G in the other thread?)

Hope I made sense there...

Just learnin' is all.

Thanks,
Pete

[astor]

you need to aclimate the wood for a week or so,in such a small room, unless extreme humidity exposed,it should be ok.
Be sure to lay down Aquabar or similar moisture barrier under the wood.

[Floordude]

Originally Posted by fixitpete

Understood.

In a small room, say 10x10, the expansion joint is simply the space left around the perimeter of the room, correct?

No, that is called perimeter expansion space. If a floor swells enough to take up the required perimeter expansion space, it will buckle out in the middle long before that happens.
An expansion joint is used when installing in the winter time, and the wood is showing lower then average moisture content. Come summer time, the floor swells and takes up this gap left on purpose. This is were knowing the shrink & swell coefficient of the species of wood is very much needed, to calculate what that floor is going to do as it gains moisture content.

Originally Posted by fixitpete

With that being said, and floor being made up of many boards (in my case 3.25") why would the the planks not buckle at the T&G?

(Just like you would see gaps @ the T&G in the other thread?)

If the pressure exerted is enough, the floor will buckle as it swells. If it is fastened really good, it compresses the edges of the boards, which gives it a cupped appearance, this can cause compression set, which is a permanent condition, even as the floor gaps in the winter, the boards will remain cupped. They can only compress so far, and then everything heaves at the point of least resistance.

[hawaii]

If he moisture between the wood and subfloor it close is should not buckle.
Make sure to acclimate before you start to install hardwood floor
There can be some extreme expousure to the diferences of moisture or temperature in the futer and this might cause buckling.

[Floordude]

Originally Posted by hawaii

If he moisture between the wood and subfloor it close is should not buckle.

That is not always the case.

[PrecisionFloors]

Originally Posted by Floordude

No, that is called perimeter expansion space. If a floor swells enough to take up the required perimeter expansion space, it will buckle out in the middle long before that happens.
An expansion joint is used when installing in the winter time, and the wood is showing lower then average moisture content. Come summer time, the floor swells and takes up this gap left on purpose. This is were knowing the shrink & swell coefficient of the species of wood is very much needed, to calculate what that floor is going to do as it gains moisture content.






If the pressure exerted is enough, the floor will buckle as it swells. If it is fastened really good, it compresses the edges of the boards, which gives it a cupped appearance, this can cause compression set, which is a permanent condition, even as the floor gaps in the winter, the boards will remain cupped. They can only compress so far, and then everything heaves at the point of least resistance.

Yup. Seen it done with pennies every few rows, on a site finished floor installed in December. New construction home with no HVAC

Sand & Finish crew came back in May and did their thing, floor looked great.

[fixitpete]

Thank you very much for all the info. I will likely do the install when the site is at average temps. (April/May) and when I am happy with the humidity issue (being abated now).

You guys REALLY know your stuff and I just want to say thanks in a big way!

So THANKS!

[Floordude]

Originally Posted by PrecisionFloors

Yup. Seen it done with pennies every few rows, on a site finished floor installed in December. New construction home with no HVAC

Sand & Finish crew came back in May and did their thing, floor looked great.

Ya, there is a crew here that use pennies at about a 5-6' interval across the floor, even when installing during the humid summers. It is a canyon with exposed and loose nonengaged tongues come winter time. They don't get it!

Really the proper way is to leave that calculated gap between each row and not one big one at intervals. But in the name of production these days, the time it takes to do that, is seldom taken in the name of the lowest cost possible attitude.

[fixitpete]

Originally Posted by Floordude

Ya, there is a crew here that use pennies at about a 5-6' interval across the floor, even when installing during the humid summers. It is a canyon with exposed and loose nonengaged tongues come winter time. They don't get it!

Really the proper way is to leave that calculated gap between each row and not one big one at intervals. But in the name of production these days, the time it takes to do that, is seldom taken in the name of the lowest cost possible attitude.

What do people use for the gap?

The penny idea sounds like a) too much b) silly. IMHO.

Once I have equilibrium between materials moisture and subfloor moisture I will proceed. NOT until then.

(And then when I do, you know darn well I'll be here with my readings.)

[Cdat]

Originally Posted by fixitpete

What do people use for the gap?

The penny idea sounds like a) too much b) silly. IMHO.

Once I have equilibrium between materials moisture and subfloor moisture I will proceed. NOT until then.

(And then when I do, you know darn well I'll be here with my readings.)

Ya know the head space & timing gauge for a Ma Duece? .005 or something like that? It works great.

[fixitpete]

Originally Posted by Cdat

Ya know the head space & timing gauge for a Ma Duece? .005 or something like that? It works great.

I swear that is EXACTLY what I thought the right answer would be. A spark plug gapper was my thought!!

LOL. I'm learning a lot of cool crap on here! Guess I should do some work. God knows I'm not framing.

[hawaii]

What do you mean by pennies?
Floor dude what else would you do if the moisture in the subfloor is the same as the moisture in the floor to prevent from buckling?

[fixitpete]

Originally Posted by hawaii

What do you mean by pennies?
Floor dude what else would you do if the moisture in the subfloor is the same as the moisture in the floor to prevent from buckling?

I thought if the moisture level is equal in both sub and material, and it wasn't above a certain level, you were good-to-go... provided the area was under a certain size.

Over a certain size you use spacers... something like the gap tool for setting spark plugs.

What the heck did I miss NOW.

[Floordude]

Originally Posted by fixitpete

What do people use for the gap?

The penny idea sounds like a) too much b) silly. IMHO.

Once I have equilibrium between materials moisture and subfloor moisture I will proceed. NOT until then.

(And then when I do, you know darn well I'll be here with my readings.)

The penny, actually a washer, works in fast production gymnasium work. They put a gap about every 6-8 feet across the room, all the way down the rows. Now do that in Mrs. homeowner's home and see if you instantly are putting out a fire. It is better to have small "normal" gaps every row, then a big one at intervals across the floor, when Mrs. homeowner is involved. The deal is, rarely one thinks about expansion in the field, that is what keeps us wood flooring failure investigators job security.

Equilibrium is fine, it is nice, but what if it is winter time and the equilibrium after sitting for a month in the heated room, is 6% moisture content The subfloor is even real close or right at 6% You know the interior during the summer can be 40-50% rH, even with the AC cranking, even higher rH if they like to throw the windows open all spring.

What ya going to do?

You know the world had wood floors way before HVAC, humidifiers, and dehumidifiers.

[Floordude]

Originally Posted by fixitpete

What do people use for the gap?

The penny idea sounds like a) too much b) silly. IMHO.

Once I have equilibrium between materials moisture and subfloor moisture I will proceed. NOT until then.

(And then when I do, you know darn well I'll be here with my readings.)

Originally Posted by hawaii

What do you mean by pennies?
Floor dude what else would you do if the moisture in the subfloor is the same as the moisture in the floor to prevent from buckling?

Just because the subfloor is identical in MC as the wood, just means the wood acclimated to the present conditions, what ever they may be.
What is the average yearly moisture content for your region of the map? That is what I want to know, shoot for and maybe jiggle it, depending on the habits of the occupants.

[fixitpete]

Everything you say is making VERY good sense. The flooring (in my case) to be installed is being done in a VERY high humidity coastal area. (Tidal water 20 feet away!). Right now things are cold and (drier) than normal -- so all the tongue and grove bead board ceilings are contracted. Come summer when humidity levels are THROUGH THE ROOF and the air conditioning isn't on (it is a home that isn't used everyday) Those "gaps" in the bead board go bye-bye... I would have to think the same for the flooring...

This is getting VERY interesting.

[fixitpete]

With that ^^^ being said... doesn't it make more sense to install the flooring at a time when everything is at the most "average" (not too cold/hot/humid) - and maintain it there for a set amount of time. And THEN allow things to go back to the normal expansion and contraction cycles?

[sparehair]

Originally Posted by Floordude

The penny, actually a washer, works in fast production gymnasium work. They put a gap about every 6-8 feet across the room, all the way down the rows. Now do that in Mrs. homeowner's home and see if you instantly are putting out a fire. It is better to have small "normal" gaps every row, then a big one at intervals across the floor, when Mrs. homeowner is involved. The deal is, rarely one thinks about expansion in the field, that is what keeps us wood flooring failure investigators job security.

Equilibrium is fine, it is nice, but what if it is winter time and the equilibrium after sitting for a month in the heated room, is 6% moisture content The subfloor is even real close or right at 6% You know the interior during the summer can be 40-50% rH, even with the AC cranking, even higher rH if they like to throw the windows open all spring.

What ya going to do?

You know the world had wood floors way before HVAC, humidifiers, and dehumidifiers.

The real question is whether the world had wood floors before pennies.