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DoRight's picture

What are the pros and cons of various 3/4 inch wood subfloors over joist spaced 16 oc?

Years ago I helped to build a house with straight up 3/4 plywood.  It was covered with 5/8 inch partical board also.  Never had a squeak or bounce or springiness anywhere.

Today it seems everyone is talking about T&G plywood.  Why?  Is it really necessary?

Then people talk about Advantec (spelling).  I understand it is a protection against water during construction.  Is that necessary if you are not building under very rainy conditions?  Is it T&G as well?  What is a rought estimate of cost differentials here?



Advantec seems to be the holy (post #207297, reply #1 of 21)

Advantec seems to be the holy grail. I've never heard of anyone who was disappointed in the performance of it.

DO I need the Holy Grail? (post #207297, reply #2 of 21)

Do I need the Holy Grail?  How much of a premium does it cost?  Is it worth it?  If exposed to "extreme" elements for some time I can see where a guy would pay someting for it/  But ?????? 


do (post #207297, reply #3 of 21)

You need to study it.

Don't just take the word of people here or users.  Go to their site, find a rep, attend a trade show where you can see test displays, pic up the literature and question the booth personel.

I can't anwer any of it as I've not done an addition or new house since it's inception and availability in my market.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Do Right (post #207297, reply #20 of 21)

is your pseudonym a satirical thing ?.......huh ?


comparing apples to apples...

1st.. a good subfloor should be 3/4" minimum  and T&G

so.. from worst to best...





the pricing is all over the map  and  changes constantly.. you need a quote if  price is your main criteria..

mine isn't, so I get a quote  from my three main suppliers for Advantech only.. since it is the only subfloor we use and have used  since I discovered it about 10 years ago

Mike Smith Rhode Island : Design / Build / Repair / Restore


I did not stress enough in the previous post.............. (post #207297, reply #5 of 21)


Advantech is more than just a water repellent sheeting.  You need to look further.

As far as cost vs.   ?,         it's been said - call your supplier.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


It's all in the details.. (post #207297, reply #4 of 21)

You could do a decent job no doubt with the old methods, sans the particle board. Especially with 16" centers.

Big bragging point of the newer 3/4" t & g systems is that it is a one layer method suited for many finish flooring methods.

Some of the newer subfloors come as both t & g and square edge, either could be the best for a given situation. 

There is no way to give a current estimate of cost differential without calling the local supplier, even locally it changes often.


With 16" centers I would consider 2 layers of  7/16 osb if I was building for myself [one before and the other after dry in with felt between] but homework is required here.....

Knee jerk answer here for a local customer   is 3/4" t&g advantec or sturdifloor..


Thank you (post #207297, reply #18 of 21)

Thanks to oldhand and opps and any others who have offered their respectful replies to the extent of their knowledge.

Thank you.


Subflooring (post #207297, reply #6 of 21)

From Advantec I don't know.  With T&G, one advantage,  it is very unlikely to ever need any type of blocking. Never at 16" centers. 

As to cost, how is it that  a 2 ply system (3/4" + 5/8") that you propose using,  could be less costly than a single ply of 3/4 T&G.  Especially considering LABOR and material.

Certainly, there is nothing wrong with the system you propose.


Subflooring (post #207297, reply #7 of 21)

I did not propose a two layer (plywood and particale bd).  I stated that we had done taht 30 years ago.  It seems no one does that any more.  My currect house has 3/4 plywood ONLY and it seems fine.

So I was thinking a single layer of SOEMTHING would be fine.  But what layer and why that one?


do (post #207297, reply #8 of 21)

Did you take the time to check up on the claims from Advantech?

Did you call your supplier and ask how much?  remembering of course if it's the same as the osb market-it changes quite often?


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


No (post #207297, reply #9 of 21)

No, I have not made any inquiries other than to ask for opinions on this board.  I am a bit surprised that there are not more opinions on the subject.  It seems that most builders just default to Advantec and homeowners must not ask if there are cheaper options.  Not too surprised about that.  I doubt many homeowners ask their builder about I-joist vs dimension lumber joist either, they are justs part of teh package for most people.

I suspect most builders know that Advantec is likely to not be an issue ever, even if a problem is only a problem one out of 100 (just and example).  It is just the no sweat way to go an it is the homeowner's $, so ....

Just another one of those, "that is the way we always do it".

Of course I will ask a supplier about pricing.  I just thought there would be some rough knowledge about pricing here and opinions about whether it is worth it.  I realize prices change daily, however, for a lot of things of this nature the price of one alternative goes up or down with the opposing option, so you can get an idea of a comparison.  Is one typically a 20 % permium or 40$ etc.  Yes , it is an easy call to a supplier.  Will do.


How 'bout this.. (post #207297, reply #10 of 21)

You report back on what is available to you in your area with the prices and we critique?

Also an estimate of how long it will be in the weather and how much rain would be normal during said exposure.

Wouldn't hurt to include what the finish flooring will be and is this an owner build or contracted?


I could go on...


Yea, I could (post #207297, reply #11 of 21)

but then I would be indulging a ....


no need to be snarky... (post #207297, reply #14 of 21)

My request was an honest effort to help you out.

The answer you seek isn't black and white or universal, it requires the unique details to be accurate.

I have used many brands and types of subflooring over the years.

If I were starting a project tommorrow requiring subflooring in any sizeable amount it would include a call or two to  a couple local suppliers about subfloor availability and price. I would have an idea in mind as to how long it would be in the weather, etc., etc., and choose from those facts. That might or might not leave me making the best choice but the result would be my best effort. 

For example last summer osb sheathing went up $4 a sheet over the weekend while plywood did not.... it's not a simple world.  


I mean really. (post #207297, reply #12 of 21)

Unless this board ahs degraded to attacting nothing more than hacks, it is a pretty simple question. 

Anyone who builds regularly, which used to be the type of people posting here, should know if Advantec runs a $1 premium, or a $!0 premium, and should be able to make a first pass comment as to the rough durablity or lack there of non-Advantec plywood.

But some people just wish to be .....


ok do (post #207297, reply #13 of 21)

If you don't find anything here that makes a difference, there's other places to go.



One more thing.

I'm no hack.


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


(Reminds me a bit of (post #207297, reply #15 of 21)

(Reminds me a bit of programming forums where I hang out.  Kids come on and say "I don't know how to do X", when clearly what they're saying is "I was too lazy to look it up in the manual, and too lazy to experiment a little."   They get responses of "RTFM" and "What have you tried".)

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Maybe they have a point. (post #207297, reply #17 of 21)

Maybe those kids have a point.  Apparantly you don't know X about this subject.

I thought this was a place for friendly Q&A for people with more time on their hands than they know what to do with.  I guess SOME  people are too busy to be of any friendly value but not too busy to spend the time posting crap. It really is amazing.


No you are not. (post #207297, reply #16 of 21)

Calvin you are cool ... most fo the time.  LOL.

I believe you said you did not use the stuff or something to that affect.  Nothing to argue there.

But good Lord if someone uses the the stuff is it that difficult to say "last time I bougth ply it cost X and Advantec it cost Y?  Really?  I think people just look for ways to AZZs. 

And is it difficult to give a testimony?

If one does not have something to say on the subject or knows nothing, there is no harm in that, but way be asn AZZ?

I'm just saying.


OSB vs. Advantech (post #207297, reply #19 of 21)

Tand G subfloor is good practice because it alows the panels to move with changes in temp and humidity. Square edge panels don't allow this. To get the benefit of T and G, you shouldn't beat the sheets together when installing them. It defeats the intent.

As far as Advantech vs. other panels. Advantech has excellent water resistance, which solves a big problem for builders. Commodity OSB will swell at the edges if it gets wet. If you don't let the panels get wet using a lesser-quality product shouldn't matter. When pricing is favorable, I like plywood. It's just nicer to work with.

As others have suggested, the panel and lumber market varies a lot, so you need to call your local suppliers for pricing before any meaningful comparison between products can occur.


Patrick McCombe

FHB Associate Editor (and former building materials salesman)

Thanks Patrick (post #207297, reply #21 of 21)