Hello,
First time posting to the site but have been reading and learning a lot up to this point. Thanks to everyone for their help. Here are my project details.

Area to be covered will be 500 sq feet and encompass the LR, kitchen and hallway. Currently the kitchen, hallway and 1/2 the LR has solid, T&G pine or fir that has also been face screwed and plugged on all the ends. Its been down for several years, is really ambered and has one area with some pretty good scratches from pets. The other 1/2 of the LR has carpet with the dreaded particle board underlayment. I would like to have a consistent floor throughout and the pine or fir (can't figure out how to upload pic) just isn't my thing.

We will be doing the demo. The particle crap, I mean "board" is 1/2" and nailed with ring shanks. I know this because I've already torn it out of 1 bathroom so I know it won't be fun but we know what we're up against. The pine floor face screws I assume can be dealt with a hollow core bit. Again, not fun but it is what it is.

1. The subfloor is 2 X 6 T&G planks over 4 X 6 beams spaced 4 ft on center. From what I have learned here I would have to lay down 1/2" plywood over the 2 X 6 planks before installing a finished floor. Because of clearance issues (existing kit cabinets, front door and ability of dishwasher to be replaced) that pretty much rules out solid so we are looking at engineered.

Even engineered wood at 1/2" whether its nailed or floated (which I would be adding even more with the underlayment) would put me at an inch or more and I wouldn't think anything thinner than that would be worth putting down. Is there any wiggle room on the 1/2" ply? Could I use 1/4" or 3/8"?

2. Second question is humidity. The annual RH of Portland Oregon ranges from 60% in the winter months to 85% in the summer months. I bought a hydrometer at HD yesterday. Right now it is 68 degrees with 42% humidity and the little house icon is fluctuating between low and OK. I'm confused as I wouldn't think 42% would be considered low humidity? We just had the wettest February on record here. I've only lived here 2 years but summers did not seem particularly muggy here.

I have forced air heating and A/C which I don't usually turn on unless its over 90 degrees because the heat doesn't bother me but I realize it will bother my floors alot more. I have a vented crawlspace with vapor barrier and 2 sump pumps. One is under the main living area and the other is under the master bedroom which appears to have been an addition from several years ago. They are pretty busy when its raining hard. The grading around the house is good, we clean our gutters regularly and shut our vents for the winter and open them in the summer.

Am I destined to never have hardwood floors in rainy Oregon? The existing pine floors seem to be doing okay without dehumidifiers? While there are minor gaps (straight pin size) there's nothing horrible but then they,ve been down for several years.

Anyway any suggestions or comments would be greatly appreciated.

Thanks, Karen

I am an amateur but have been researching some people of the topics you've brought up. So take my comments with this in mind.

It could be that dealing with the front door and temporarily removing the cabinets and dishwasher makes it possible for a better job to be done. You will figure out if this is true.

Engineered is ok but falls short in terms of standards. What is the dimensional change coefficient for a given engineered wood flooring product? What is the Janka rating? Hoping someone can directly answer these questions but I have been reading for several months and haven't found either of these answers. It would appear that engineered flooring sells so well that there's been no effort to quantify hardness or dimensional change coefficient.

Dimensional change coefficient is the amount of expansion or contraction that ocurrs based on a given change of humidity and temperature (much more so humidity).

I wonder if there will be a plethora of folks having to remove glued down engineered hardwood due to wear in 10 years or so? That can't be an easy job. If I had to use engineered flooring, I would try to buy the thicker stuff and staple it rather than glue it.

On to regular hardwood. Sounds like you might choose engineered but this may be helpful to others. There are several things you can do to retard the effects of humidity. You probably won't need all of these measures but rather this is a list to choose from. Use rift sawn, quarter sawn or a combination of those (rather than plain sawn). Don Bollinger mentions on his site (woodfloorco.com) that sealing board ends with a partially pervious sealer can slow the movement of humidity into the wood (not sure of the recommended product just yet). Use narrower boards rather than wider ones (less than 4"). Use trowel-on adhesive and cleats rather than cleats only to restrain wood movement.

On any install it seems to be best to put the humidity level at its annual midpoint. Then use a moisture meter to wait for the subfloor and hardwood to reach EMC and be within 4% of one another. A humidifier or dehumidifier may be necessary.

Sounds like subfloor stiffness may be an issue between floor joists. There are guidelines for subfloor thickness based on floor joist spacing in Don Bollinger's book. I'll have to look those up and get back with you.

Thank you Pml for taking the time to respond.

The reason I was considering engineered is it appears it may have more stability than solid hardwood and that I may get away with not having to put down at least 1/2" plywood over my 2x6 T&G planks on 4x6 beams. That type of subfloor is quite common here and it seems plenty stiff. Right now the existing solid pine T&G floor is nailed directly (perpendicular) onto the 2x6 planks. There is a roofing felt underneath.

Oregon is considered to be pretty humid but I've only been here 2 years. So I bought a hygrometer (not a hydrometer as I previously posted) and have been tracking it a few days. I know its all relative but right now it says it 66 degrees and 45% humidity and the little icon reads low. If the home should be kept at 40 to 60% RH and 45% is considered low that seems a pretty small window.

I'm hoping to hear from someone if I could put down less than 1/2" plywood over my existing 2x6 planks or if it is necessary. Would I be better off with an engineered or solid?

I have been looking at solid engineered. Vintage Flooring has it but there is no dealer near me. Oregon Lumber Company sells it but I bet it is pricey and near the 13 to 15 dollar range. But they say that their solid engineered can withstand a wider range of humidity scenarios for 20 to 70. The only problem is all their planks are wide (over 7").

I'd hate to have to reset the front door and my kitchen cabinets are old and appear to be built in so it might be problematic to try and remove them and then reset them after beefing up the subfloor. Its a small kitchen but still it would add on another expense for new cabinets.

Hopefully I hear from some other members but I do appreciate your thoughts. Its a journey!

Karen

I would have no problem gluing an engineered plank down that is 3-4 inches wide with a three millimeter or more veneer for the surface. You may be able to sand it more than a few times, but if you like the color after 5-10 years you can re-coat it successfully if it has a surface film type of finish with no waxing, ever, just cleaning when it gets soiled.
I would prepare the T&G plank sub-floor by sanding high spots, cover any knot holes with galvanized metal and then lay the flooring across the sub-floor planks. Glue and fasteners like 18 gauge brads to hold the planks in place until the glue sets should be fine. 5/8ths inch thick flooring would work.
If you want a hard surface then find a color that you like with a high janka rating.

Hey Pete, thanks for your input.

Just wanted to clarify about the sub floor prep:



If I glued a good quality engineered flooring (at least 5/8" thick with at least a 3mm veneer) directly to the 2x6 T&G subfloor planks it seems to me I would not be able to lay down a vapor barrier (roofing felt or Aquabar) which makes me nervous? And gluing directly to a subfloor without an underpayment seems contradictory to what I've read here but maybe I'm just not understanding you correctly.

The subfloor will need prep to be sure, high spots sanded down and low spots built up. What I'm trying to do is determine if I must put 1/2" plywood on top of the 2x6 T&G plank existing subfloor (which is what I've read here about subfloor prep) before I lay my engineered flooring or can I get away with 3/8 inch plywood?

Do engineered floors always have to be glued and nailed or can they be just stapled?

Thanks again, KJ

You can buy a glue that claims to be a moisture barrier and glue directly to the sub-floor planks, going perpendicular the the direction that they are laid. The engineered flooring will not be as susceptible to moisture changes as a solid. I would glue the engineered plank to the sub-floor sub-floor, using 18 gauge staples to secure the planks until the glue sets up, so the planks don't shift when you are installing. Three-eighths inch plywood should work, if you want to with go that method, with a fastening schedule of 4 inches perimeter and 6 inches field.

Thanks Pete,

Does engineered flooring always need a full adhesive spread? Any particular reason for not just stapling? Besides the 3/8 inch plywood I would put down there is a 2x6 plank subfloor underneath so it seems there is plenty of wood to staple into. Is this determined by the thickness of the engineered flooring 3/8, 1/2, or 5/8 inch? or does gluing make it less susceptible to expansion and contraction?

Thanks again for your time, Karen

I don't think that engineered flooring needs to be glued, like solid when it is wider than 4 inches.18 gauge staples an inch and a half long work fine for up to one-half inch thickness engineered flooring. Gluing will make a more solid feel and help with extreme moisture content variation, like a water spill. An engineered plank is much more stable than solid wood. If you are going to lay the floor parallel to the planks the plywood will be a good underlayment.