This subject really is the one I get most correspondence about, its a fairly simple process really but if its done badly or you don't know what you are doing or what products you should use then things can go very wrong very quickly.
This Blog is about Gap Filling your wood floor, it doesn't matter if you have a beautiful hardwood Oak Parquet Block floor or old softwood Pine Floorboards, the principles are the same as is the method for getting the job done. The Gap Filling part of the Sanding & Sealing process is carried out shortly before applying the first coat of seal to the floor so it really does need to be done correctly otherwise your floor could easily look a mess.
Two main components are needed for Gap Filling are some nice clean fine sanding dust from the floor/species you have been sanding, and the Filler itself.
There are two distinct product types in the Filler market, Solvent Based Fillers v's Water-based Fillers, both have different properties and behave differently, for example the solvent based fillers have a quite pungent smell when used, and the Water-based fillers don't, with solvent based fillers you have a quite short working time whereas the water-based fillers have a long open time.
I can tell you are leaning towards the water-based products already :-) but before you make up your mind read on.
From a Professional standpoint I personally almost always use solvent based fillers, this is because a solvent based filler dries really quickly [10-15 mins] and most of the filling I do is for relatively small area's in respect of the overall job. I need the filler to go off quickly to be able to move onto the next phase of the operation which would be to properly Sand off any residues and to finish the preparation on the newly sanded floor.
The two above pictures are of the exact same area from a recently completed job, where the pictures clearly show the dramatic difference that applying filler can make, in the top pictures your eye's are drawn to the 'black gaps' that can be seen pretty much everywhere in that picture. In the lower picture you can clearly see the difference that the gap filling has made - believe me that particular floor took some gap filling :-((
Click on the link and you will be taken to the complete Gallery of that project - the before and after pictures are quite startling Conwy Valley Pitch Pine Job
The main component of gap filling is the dust, make sure it's nice and clean and at least 80 grit and finer, meaning 120 grit dust is better again, mix the filler into the dust, to the consistency of a thickish custard, don't worry if you pour on too much filler and it goes very runny, simply add more dust and mix well.
When properly mixed you basically scrape the mixture into the gaps, somewhat similar to grouting tiles. I would advise using as wide a scraper as possible as gap filling can be a very time consuming and tedious job if all you have to use is a 4" wallpaper scraper.
When properly mixed you basically scrape the mixture into the gaps, somewhat similar to grouting tiles. I would advise using as wide a scraper as possible as gap filling can be a very time consuming and tedious job if all you have to use is a 4" wallpaper scraper.
As soon as you apply the filler mixture to the area you are filling, make sure you scrape off as much of the residues as possible, as when the filler dries, it dries hard and can be difficult to remove if thick residues have been left on the floor to dry.
Remember - Solvent based fillers have an approximate 10-15 minute working time, while the water based fillers have a much longer open time, and can be as much as an hour or more before it is properly dry depending on how wide the gaps are...the wider the gaps the longer the drying time and that refers to both filler types.
Hope this article helps - Good Luck with your project.
If you use a solvent based filler, is it stainable? Here is where I am not in the project. I have sanded down the floors (yellow pine) and I planned on using the dust to fill the gaps, but when I sanded my floors they were a darker color, now they are down to the bare wood. I plan on staining the floors after the gaps are filled. How do I make sure that they will match?
ReplyDeleteHi jstarbuck
DeleteIn answer to your question, you can fill the gaps in your floor and then stain, both solvent and water based fillers are designed to be able to accept the coat of stain [presumably darker in your case] and should look almost identical to the way that the stain takes to the timber.
i've done the same as what you are attempting to do on many projects and the results have always been good.
Hope that helps - Good luck with your project.
hi, I had my parquet flooring fitted 8yrs ago. due to us renovating the house, we had no central heating. we layed the floor when it was cold, then 6mths later we had A central heating system fitted, the floor has shrunk back, 2mm-8mm WORSE CASE. I AM A CARPENTER AND IM DUE TO RENOVATE IT. I FOUND UR ARTICLE VERY INTERESTING, BUT IVE GOT ONE CHANCE OF GETTING IT RIGHT AND FILLING THE GAPS INBETWEEN. HOW WOULD U GO ABOUT DOING THIS PROJECT AND WHAT MATERIALS WOULD U USE. PLEASE HELP AS UR THE EXPERT.
ReplyDeleteHi Kian
ReplyDeleteIn my opinion the wider gaps in parquet floors are better filled with a solvent based filler such as Lecol 7500 or Junckers Basefill, either of these fillers would be ok for your project, but bear in mind as the gaps in your particular parquet floor may be quite wide, you may have to do the filling a couple of times to the wider gaps as very often the filler will sag a little, leave the filled gaps for a few hours [or more] to go off then do them again [if needed]
Another tip would be to use as finer floor sanding dust as you can, the finer the dust the better it will mix, and the better it will look in the gaps in the floor, use 100 grit sanding dust if you can, as i mentioned the finer the better, mix the dust/filler to a thickish custard consistency.
Don't use coarse sanding dust as it just doesn't bind together as well as the finer material.
Its not a bad idea to do the mixing of the filler in an old [or new] washing up bowl, it will save the filler getting everywhere.
Hope that helps you and good luck with your project.
Regards Gary
Woodfloor-Renovations
HI GARY, THANKS A LOT FOR THE ADVICE. HOWS ABOUT I PAY U £10.00 SO THAT U CAN DO IT FOR ME, LOL, AND I'LL MAKE THE TEA....
ReplyDeleteIT IS AS EASY AS THAT,
SAND THE TOP COAT FIRST, THEN THROW AWAY.
SAND THE SECOND COAT (WITH 100 GRIT SANDPAPER),
GATHER THAT DUST,
MIX WITH JUNKERS BASEFILL (MIX LIKE CUSTARD),
GROUT HE FLOOR, LIKE U WOULD WITH TILES (SEVERAL TIMES FOR BIGGER GAPS),
THEN SAND FOR THE FINAL TIME.
WHAT WOULD YOU USE, FOR THE FINISH, LIKE A CLEAR VARNISH.
Where you use the sanding dust from, which would either be from the main sanding machine or the edger, the dust from the main sanding machine would likely be too coarse, even dust from a 100 grit sanding abrasive.
ReplyDeleteThe trick would be to use the dust from the edging machine from either a 60 or 80 grit abrasive, the edger dust is just much finer than the main sander, the more floury the dust the better.
Sanding off the filling residues with the main sander is a good idea [its what we do mostly] but to get a smooth finish we ALWAYS use a buffing machine with a 60 grit followed by either a 100 or 120 grit, these final two processes close the grain of the wood properly and leave the wood surface smooth and ready for which ever type of seal you choose to apply.
If the area you are restoring i'd go for a good quality lacquered finish, 3 x coats is a standard that a professional company will quote for, but you can add as many as you like...its up to you.
Hope that helps and good luck with your project.
Regards Gary
Woodfloor-Renovations
2 LAST QUESTIONS, THEN I WILL LEAVE U ALONE.
ReplyDeleteSHOULD I USE THE CIRCULAR FLOOR SANDER OR THE FLOOR BELT SANDER??
WHAT IS THE NAME FOR A GOOD QUALITY LAQUER, TO FINISH??
THANKS A LOT FOR ALL THE GREAT ADVICE...
The quick answer to your first question is BOTH, I usually do 3 processes on the belt sander, then 2 processes on the buffing machine, there are many good quality single component lacquers to finish your floor, Bona Mega is one, Junckers Strong another, and Lecol Lobadur Viva is a lesser known but equally as good product.
ReplyDeleteI have put the products in a descending order of cost...all of them will look sensational if you apply them properly...good luck
thank u ever so much, for spending the time to help me, to do the best project on my floor. its been down through 2 baby's - toddlers and 8yrs
ReplyDeleteof having a battering. time to give it a makeover.
once again, thanks a lot.
No worries Kian, hope your project goes well for you.
ReplyDeleteRegards Gary
Hi Gary, great blog. I am worried about further movement opening new gaps after I have spent all that time restoring the floor. The gaps I would fill are up to 3.5mm wide. I was also thinking of gluing in thin wood slivers, what do you think?
ReplyDeleteGaps tend to open/close mainly with seasonal changes [moisture levels in the air]
DeleteAt this time of year [summer here in the UK] gaps tend to close up [expand] mainly due to the higher humidity levels and latent moisture in the air, which combine to make the wood swell slightly causing gaps to close/tighten up.
From around October through until march/april time [in the UK] is a much drier time [humidity/moisture wise] which is the approximate time that a wood floor will usually contract [shrink]
For gaps of around 3.5mm i personally wouldn't put slivers of wood into a floor, especially if the tongues of the timber floor are still in place, as when you properly gap fill a wooden floor its much better if the tongues are there as they will stop the filler falling straight through the gaps to the void underneath.
You could try a colour match mastic filler for your floor, such as Bona Gap Master, which is pretty easy to apply and the results can be very good.
Hope that helps.
Regards Gary
hi, again.
ReplyDeleteI was going to rip up the old floor, and lay a new floor, purchased from a salvage yard, due to the damaged blocks, by traffic.
by doing this, I know that all the blocks would be of the same timber.
im going to self-level the floor, then sand any waves out.
what adhesive would you use.
I was told that I can leave the old tar on, just scrape the snobs off, is this true.
This comment has been removed by the author.
ReplyDeleteYou need to scrape off as much of the residues as possible, regardless of what you were told...if you don't you will risk the adhesive not adhering properly to the bottom of the blocks.
ReplyDeleteAs for adhesive, my personal favourite is Lecols [now Wakol] 5500 parquet adhesive, its a fantastic product that has worked flawlessly on all the projects i've used it on [hundreds] i've yet to have a block not stick down properly.
Hope that helps.
Hi
ReplyDeleteI am sanding a hardwood floor from1900.
When done sanding I was planning on filling any gaps between the boards with the dust / filler and staining the wood floors.
I have also read NOT to fill the gaps or it will later come out when temps change summer/ winter. The gaps are the size of a dime or so.
Is this true that it will fall out of the gaps later ?
Thanks
Hi Robert
ReplyDeleteI've gap filled hundreds of floors like yours, and while its pretty certain over time some [small percentage] of the filler may come out with seasonal change and board flex, the vast majority will stay in place...If the gaps in your floor are only the width of a 'dime' and you feel for aesthetics they need filling i'd recommend doing it !!
Just make sure you use fine sanding dust and a good quality filler, take your time and do it properly, the results will speak for themselves.
Good luck with your project.
Regards Gary
Hi Gary
ReplyDeleteThanks for your advice on filling the small gap lines between the boards.
I also will be using a stain mix of ZAR cherry/teak it is sort of a dark cherry.
Will my saw dust mix with Junckers stain the same color as my sanded floor.
I have tried other fillers and they didn't stain even close to my wood color.
Could you also advise me on the correct sanders and grit to use.
I was planning on a using a belt sander to knock down the top coats / old stain and then a lighter grit after and then use that saw dust.
Should I use a buffer sander after filling the gaps and what grit before staining ?
Do you also go over the poly coats with a buffer and what grit do you use between each coat ?
Also the kitchen had old linoleum over the wood floor and we removed it and glue was used to hold down the llinoleum. Is this ok to sand or should it be checked for asbestos first ?
Thanks Again
If you use Junckers Basefill as your gap filling product, it should take the stain you are applying to the floor very well [it has done many times for me]
DeleteUse good quality sanding machinery such as Bona or Hummel, the basic hire shop machines are poor quality to put it bluntly, pay a bit more and get the good stuff.
Depending on the condition of the floor, we often start sanding a floor on P36/P40 grit, then move up to P60, then either a P80 or P100 depending on the floor type/condition, then bring in the buffer with 2 courses of P60 then P100 or P120, vacuum between every stage as a matter of course.
May be a good idea to check the kitchen floor for old adhesive residues [asbestos] better safe than sorry.
Good luck with your project.
Hi Gary. Can I use a PVA mixed with the fine dust to fill a 5 finger parquet floor? Don't have basefill to hand! Thanks Ray.
ReplyDeleteHi Ray
DeleteI've never used pva and fine dust so i can't really say it will work for you, but try doing it on a small area first and see how that goes...
Hey Gary
ReplyDeleteI am going to sand all the floors in my house and was wondering what the best way to fill all the damaged boards. They are old pine boards from 1885 and have a very reddish tint to them. Is it best to use Solvent or water based resin mixed with sawdust do this?
Also is there any particular brand of resin filler you can recommend? Have been looking at lecol 7500. Have you used it and would it work with old pine boards. The plan is to treat them with white lye and oil afterwards?
Hope you can help
Brian
Hi Brian
DeleteYes we use Lecol 7500 filler on a very regular basis, its and excellent product and has always works well for us, use as finer dust as possible, 80 grit from the edging machine is usually very good to use, it will bind well with the Lecol 7500 and should trowel into the gaps nicely.
The white lye should cover the colour of the gap filler ok.
Good luck with your project.
Hi gary,
ReplyDeleteI had my parquet floor restored in July 2017, this was a full sanding, filling and restained. The floor in my living room has started to open up since early December and in the past month more have appeared, they seem to run in sections . The living room does have a woodburner and can get warm.... the floors in the rest of the house (hallway, dining room and bedroom) are fine... any ideas ? Should this happen or should i go back to the company that did the floor ? Cheers Neil
Hello Neil
ReplyDeleteWhen you say 'open up' do you mean some of the gaps?
From what you say, and the fact you have had a new wood burner installed in the room it could simply be the room is getting too warm and the timber is drying out too much, its normal at this time of year when everyones central heating is on regularly that wooden floors start gapping, but if the other areas of your property are showing no signs of any gaps and the issue is in one warm room its likely to be its just a bit too warm and the timber is shrinking a little.
Maybe try putting a Humidifier in the room to put a bit of moisture back into the atmosphere, constant dry radiant heat can often dry out a timber, putting moisture back into the room should make a difference.
Hope that helps.
Hi gary, yes its gaps and some are up to say 5mm, ill try the humidifier to see if it restores some balance to the room, in your experience will the gaps close in the summer when the heatings off and theres more humidity ?
DeleteCheers Neil
5mm is quite a gap, but yes after March/April when the heating goes off and there is naturally more humidity in the air the gaps should close up, whether they will close fully i just don't know.
ReplyDelete