About 10 years ago we had our floors -- some hardwood some pine -- finished
with polyurethane.

They are beginning to get dull. Could I just give the floors a light
sanding, then put on one or more new coats?

I'm not sure whether oil or water-based polyurethane was used initially.
Does it matter in terms of the new coat?

I don't know the answers to the two questions you posed, but there are companies that make floor maintenance equipment to do the sanding of the polyurethane. Take a look at this web page:

Woodpecker the dustless floor sander. Use it with weights and vacuum

Centaur is probably one of the biggest Canadian companies making janitorial equipment. One of the floor machines they make is the "Woodpecker" which is basically a standard Centaur Rabbit III floor machine that connects to a vaccuum cleaner so that the machine sands the polyurethane down and vaccuums up the dust at the same time.

What I'd suggest is to phone around to the places listed under "Janitorial Equipment & Supplies" in your yellow pages phone directory and find out who in your area sells either Centaur products or any similar floor machine made for maintaining polyurethaned wood gymnasium floors.

Generally, the labour rates in the Janitorial Service sector of the economy are quite low, typically being no more than minimum wage. If you can find any janitorial company that has a Centaur Woodpecker or similar wood floor maintenance machine, they would probably sand down your floor for a very attractive price.

| They are beginning to get dull. Could I just give the floors a light
| sanding, then put on one or more new coats?
|

Not a good idea. Once it's cured it's like a sheet
of plastic. Another coat on top will often peel like
a sunburn -- little shreds here and there. I've had
good luck with sanding liquid. You don't even need
to sand. Just wipe the liquid on. (The traditional
stuff, like thin stripper. Don't get any new low-VOC
product.) After wiping it on you have about half
an hour to recoat. It works because it softens the
old finish, so that a new coat can bond to it.

"Ray" wrote in message
...

About 10 years ago we had our floors -- some hardwood some pine --
finished with polyurethane.

They are beginning to get dull. Could I just give the floors a light
sanding, then put on one or more new coats?

The chap who did our oak floor 10 years ago (still like new) said
the polyurethane finish he uses requires special handling, mainly
walling off the room completely with plastic while the toxic solvent
evaporates. This took at least 24 hours, possibly 48, but the results
are worth it.
--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

"Ray" wrote in message

About 10 years ago we had our floors -- some hardwood
some pine -- finished with polyurethane.

They are beginning to get dull. Could I just give the
floors a light sanding, then put on one or more new coats?

The purpose of sanding is to create small imperfections so that the new coat
has more surface to grab. The fact that your floors are getting dull means
they are already scratched up from foot traffic. Are they scratched up
enough so that you don't need to sand? Probably but I can't see your
floors.

Another option (to sanding) is trisodium phosphate...it cleans well and
de-glosses.

FWIW, all our floors are Saltillo tile topcoated with polyurethane varnish.
The poly lasts quite well but eventually high traffic areas need recoating.
I don't sand.

I'm not sure whether oil or water-based polyurethane was
used initially. Does it matter in terms of the new coat?

Not for adhesion. The water base won't impart the slightly yellow tint of
oil base but it is less durable.

--

dadiOH
____________________________

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Taxes out of hand? Maybe just ready for a change?
Check it out... http://www.floridaloghouse.net

| Is there any problem in putting water-based polyurethane over oil-based
(if
| that's what I have)?
|

I'm afraid I can't help with that. I've never
used the waterbase stuff except for new cabinets.
(I can't say I'm impressed with it, though it does
settle down pretty well.) As for bond, sanding liquid
makes the old poly as though it were put on yesterday,
so you're doing another coat of the same finish, in
a sense. It works great for any oil-over-oil use. I don't
know how that relates to water-base finish. In that
case the sanding liquid may not help. It may even be
worse, but I really just don't know.

Thanks. Very helpful.

Is there any problem in putting water-based polyurethane over oil-based (if
that's what I have)?

"Mayayana" wrote in message ...

| They are beginning to get dull. Could I just give the floors a light
| sanding, then put on one or more new coats?
|

Not a good idea. Once it's cured it's like a sheet
of plastic. Another coat on top will often peel like
a sunburn -- little shreds here and there. I've had
good luck with sanding liquid. You don't even need
to sand. Just wipe the liquid on. (The traditional
stuff, like thin stripper. Don't get any new low-VOC
product.) After wiping it on you have about half
an hour to recoat. It works because it softens the
old finish, so that a new coat can bond to it.

On 4/26/2014 4:21 PM, Ray wrote:
About 10 years ago we had our floors -- some hardwood some pine --
finished with polyurethane.

They are beginning to get dull. Could I just give the floors a light
sanding, then put on one or more new coats?

I'm not sure whether oil or water-based polyurethane was used initially.
Does it matter in terms of the new coat?

10 years? That seems odd. You must have a lot of traffic.

To be on the safe side strip the old coating off with floor sanders and
go with a premium quality oil based stain and polyurethane finish. I
don't think I'd use the same company you used last time. If you're doing
it by yourself, I warn you, it's a hard job.