Wooden floor sanding project

[Lacan07]

This was almost my downfall in the hallway. I got a load of testers (Morrell's I think), tried them out on a spare piece of floorboard and decided on the one that seemed to best match the doors.

After applying a couple of coats of it across the whole floor it was veering too much towards orange for my liking. Saved by a couple of coats of shellac sealer which brought it back to the more honey-like colour I was aiming for.

Unless you have years of experience doing it, I think its really difficult to tell how it will turn out until you are well committed. The thought of having to start over was just too dreadful to contemplate. Sorry Matt, not helping with your procrastination...

For the next room I may skip the stain and just do extra coats of shellac. The challenge with that one is going to be the 4 or 5 rows of replaced boards that are much whiter than the original boards.

Yeah soft pine has a tendency to go orange, its the hardest wood to stain according to Toby.

I went all round the houses when searching for a stain, I had a small stock of original boards to make samples from but soon ran out and had to re-sand the samples I didn't like to make more samples. Absolutely none of the products matched their swatch, especially looking online on a computer screen. Some of the colours / stains were dreadful imho. I ended up opting for a Jenkins 'old school' Nitrostain. Once dry the details in the wood are mind blowing, the individual knots go flame orange /red and looking through a magnifying glass you'll still never comprehend all the intricate lines.

 

[Cubist]

curious, but can you fill gaps using sawdust/Lecol paste for suspended floorboards?

In think you would need a filler material that retains some flexibility after its set - I can't speak for the Lecol product never having used it and my direct knowledge is now fairly old and I cannot now recommend an alternative - particularly if its to be used in areas of where there is some foot traffic and/or there is any movement in the boards. Stiffer materials will break up and either fall out or be removed by vacuum cleaners. The better approach may be to infill with wedge shaped strips of compatible wood if you can but that too has its own challenges.

I've been looking again at Matts diamond and trying to work out what wood was used and considering ideas for its repair. The photo may be misleading but some of the damaged areas seem to reveal lighter colour tones that suggest a base timber dyed or stained to this almost black colour. Again its difficult to see but the grain structure seems very similar to oak and for a moment, until I noticed the lighter shades, I had thought the wood may have been fumed to get that colour, but that tends to more thoroughly permeate the wood to a greater depth.

Matt - Given the condition and extent of damage to the elements of the diamond have you considered simply replacing it with some new timber? The component parts could be quickly and easily cut using a half-way decent compound saw and then stained or dyed to the desired colour.

 

[overlander matt]

There's a lot to consider on this floor. Thank you for your thoughts and for sharing your experience.

In terms of filler between the boards, some flexibility would be preferable as there is movement in the floor. Part of me thinks the gap filling is a bad idea but I don't like the small number of gaps... I might carry out a fill in a board underneath a radiator to see how it comes out. There seem to be aesthetic as well as durability concerns. The last floor finishing used something in the thinner joints - or was it just lacquer over dirt?

The floor staining is going to be a challenge. I had a pro floor guy come over who used the Bona primer and lacquer system. The clear primer he used gave a pretty good colour match. Maybe one increment darker might have been right. I have oak bannisters and spindles that I am trying to get a bit closer to on the floors and staircase.

I might use the Morrell stain. I do have some sections of floor that I can try a couple of samples on. Getting this bit wrong is a worry.

Cubist asked about the dark wood in the diamonds. I was really looking to keep it rather than replace. The wood appears dark all the way though. I too thought it might have been stained. It wore quicker than the adjacent oak leaving deep grooves in the grain and I have had to lift the dark diamond and central diamond with some 3mm ply on the joists below in order to get the floor flat again. That at least seems to have helped.

I made a start on some sanding today. I bought a new Rutland sander to replace my old Erbauer. I'm interested to know just how much to sand off. I don't want a blemish-free floor but clearly all the old lacquer needs removing. I'll post a photo or two taken when it's light.

Thanks once again.

 

[Cubist]

Hi Matt,
Hopefully you will be able to save the dark wood diamonds but I have some doubts; not least because I suspect that the extant nail damage to those sections AND the underlying joist(s) below may prevent your securing a tight mechanical grip on these parts. I'm a little loath to suggest it, but an adhesive may be the only real option.

Regarding the gaps between the boards; haver you considered using caulking cotton to pack these rather than using a filler? This can be braided, twisted and pulled to a diameter that can be firmly pressed between the boards and it will then expand to apply sufficient lateral force, as it tries to expand, to hold it in place between them with very limited risk of it falling out below. The top most surface of the cotton can then be painted with linseed oil or simply covered with a particulate filler or wax.

 

[overlander matt]

Thank you Cubist. The joists seem in remarkably good condition given the state of them in the adjacent rooms. I can hopefully get a good fixing to them. As for the diamond, it will need some filler to repair the old nail holes and damage. This was the worst of the 3 and for whatever reason the dark wood used for the diamonds has tended to wear leaving a rough grainy texture. I've sanded some of it out but it may need something else...

Having spent a few hours today with the sander with a 60gr abrasive I have discovered there is a lot more movement in the thin oak boards than I was aware of when I was looking at the Lecol filler. I think I'll be moving away from a hard filler between the boards. I must admit I was unaware of the caulking cotton approach - what size gaps would it be suitable for? I'm hoping the very smallest gaps will just be filled by whatever gets applied later on.

I've never sanded an old oak floor before. Previous homes only had pine. I have included a couple of examples from the 60gr pass. So far I have removed the old lacquer coat plus any obvious markings from the belt sander used on a previous sanding. I wasn't sure what to expect but there is a lot of variation in the colour of the sanded wood. Is this to be expected or just a sign I need to sand more?

Oak floors are tough too - a 6" abrasive disc is only stripping an area of around a square foot. Hopefully not too many more boxes needed!

 

[Cubist]

Hi Matt,
I'm going to bore you perhaps with more detail than you may want right now but.....

Caulking cotton is typically sold by weight and currently costs around £12-15 for 0.5 kilo and is mostly available from Boat Chandlers; I'll put a link to an example in the post later. Various diameters are available but the most common is around 8mm. This, when twisted and pulled, can be reduced to around 1 - 1.5 mm and even then can be compressed even further. Typical installation suggests it should be 'hammered' into place but that is really only necessary when you're aiming at a water-tight joint for a boat or say an external door frame. For internal use with those floorboards of yours a little muscle pressure under the edge of a suitable tool would be all that is required to press it into place. I've used Caulking Cotton to close any number of gaps around this place and these have ranged from anywhere between <1mm to 20+mm. For anything above 2-3mm it may be necessary to braid several strands together to form a rope of the required thickness. The Chandlers will suggest some fancy tools in the shape of a variety of what look like chisels but you can ignore these, an old dull bolster chisel, a wide blade stubby screwdriver and an Upholstery Tack Lifter are all I've ever needed - the latter is particularly useful.

The technique for installation that works best for me is to tie a knot in the loose end of the cotton and use this as anchor in the gap between boards just before a corner and then, while turning that corner, draw the cord toward you while twisting it between your fingers and firmly pressing it into the gap as you proceed along the seam. Turning the corner will also help maintain the anchor as you proceed and will help you avoid inadvertently pulling all the cord out or pulling it through along the length of the seam. The objective is for the cord to get a tight connection to the boards on each side as it tries to relax from the twisting and pulling actions. Personally I aim to find some resistance when I try to gently pull the cord out. Also, should you find that the gaps widens to a point where the cord becomes too loose, you can pull out the last few inches of cord, tie an additional cord to the the original just before the gap widens and braid them together to recover the tight fit.

Depending on your aims for the floor the cotton can be installed flush or a few mm below the final surface. I've found that a milk chocolate brown emulsion paint can be used to achieve a close match to old oak. This can deceive an observers eye and when finished with say a clear wax or lacquer look almost identical to the surrounding wood. Alternatively, if pushed down into the gap to a couple of mill, it can do an excellent job as a bed for any other filler you may use.

That aside, a few things you've said above are a trifle concerning. The first being that you're seeing, or maybe feeling, some movement, presumably vertical, of the boards while sanding. I had thought that the planks would be around 20-25mm thick and crudely compatible with the stair nosings. However, over the lengths of longest boards the photos suggest, together with the observable nailing pattern, any movement at all would be unlikely. Are the boards in fact much thinner than this or could it be that the bodies of the nails are moving inside the joists below? I see too that some of the nail heads have come into contact with the sandpaper. Ordinarily it's necessary to punch these down before sanding as the exposed head will limit the sandpapers contact with the rest of the wooden surface and the polished heads will be difficult to conceal. However, if the boards are thin there is a much greater risk of losing the mechanical connection of the nails, collateral damage to individual boards and particularly the shorter/narrower ones so great care is needed if they must be punched lower into the wood.

The sandpaper you're using is a coarse one and frankly I would have expected it to make short work of most jobs. True, oak can become exceptionally hard as it ages but even so you should be making better headway. Are the sheets you're using wearing out or are they simply clogging? If the latter it may be due to the planks being oiled and waxed long before the latest lacquer coats were applied. The oil will have penetrated deep into the timber and even now, even centuries later, it will resist removal and clog the paper. If they are simply wearing out then sadly they are not fit for purpose.

Regarding the dark wood diamonds. I'm aware of some techniques applied by furniture restorers to stabilise and strengthen wood that has become delicate and/or has been damaged but I'm not sure these would be of much help. My concern with these is that they are fairly narrow, I'm guessing circa 50mm?, and as you've mentioned earlier are around 3mm thinner than the surrounding timber. That's a worry for several reasons, the first being that these are positioned directly in the path of footfall through those spaces and some, I think, directly in front of or beside turns into other rooms and are therefore victim to weight and torque driven movement that operate against the woods fixings AND its internal structure. Also, there may be limitations posed by the dimensions and layout of the underlying joists that constrain the positions of any fixings. Filling the holes may be worth a try but ultimately, and I suspect sooner than you might like, they will fail and have to be replaced.

Sorry for the lengthy response but that floor has really capture my interest.

Cheers,
Cubist

8 Ply Best Caulking Cotton 1/2kg | Jackson Marine

Soft, top quality caulking cotton made up of eight strands totalling an uncompressed diameter of approximately 8mm. Used for the caulking and re-caulking of wooden carvel planked classic boats and new build wooden yachts. The caulking is often pushed in to place with a caulking iron, in turn...

www.jacksonmarine.co.uk

 

[Stevers]

The swirly grain pattern on the treads looks like Elm. We have Elm treads and risers on the stairs down to our basement. About eighteen years ago I stripped, and oiled them, and they are holding up well to frequent use.
The oil was nothing fancy, just boiled linseed oil let down with white spirit, the same mix that my father used for the wooden floor in his greengrocers shop.

 

[Cubist]

Matt,
Apologies but an afterthought regarding the movement of the boards you are seeing while sanding has led me to an unhappy conclusion.

The pressure you are exerting through the sander will be a fraction of that resulting from the point load of a person stepping onto the boards. That load will of course induce a more significant deflection the force of which will be transferred mechanically resulting in 'lift' directly above the fixings to the supporting joists. As the persons weight is transferred the deflection relaxes and the board ends will 'fall' back to their original resting position. This cycle of movement, repeated perhaps many times daily over decades can only have a detrimental effect on the efficacy of the nail fixings, the boards and the joists.

Unfortunately, I think that 'punching' the existing nails in, and perhaps adding more, to achieve a better mechanical connection, while this may work for a time to stabilise or limit such movement, it will ultimately fail in the same way again and perhaps resulting in more serious damage. It's not clear whether T&G or Lapped boards were used and theres a reasonable chance they are merely Square Edged. The former two would help to spread the load and reduce the impact of such movement but SE would do nothing except limit the harm to the boards of the most frequently travelled paths. Sadly I've come to the conclusion that more radical intervention would be needed to supplement the existing array of joists with additional noggins to obviate such movement in the future.

Of course, you don't need to bite this bullet right now but you might perhaps want to reconsider your current plans.

 

[overlander matt]

Thanks Cubist for your detailed thoughts about the floor. I really appreciate the interest. I've had a miserable few days off the work with some flu-type inconvenience so back to it this week...

It is an unusual floor in that the boards are much thinner than expected in a typical floor. They are just 12mm thick and square edge as you suspected. The joists are spaced to allow fixings around 200mm. I've not had enough of the boards up to fully inspect the state of the joists, but those that have been lifted have shown joists in a decent condition. The adjacent rooms had floor joists in poor condition - so much so that one room needed new timber and the other required substantial repairs using the good timber from the other room.

The floor is a little springy, which I think is not a great surprise when one considers the thickness, or should I say, thinness of the boards. I tend to think that any non-flexible filler such as the Leicol paste between the joists is the wrong approach unless it is strong enough to bond the boards together with the flexibility to withstand the movement. Downstairs is not too bad but there are a couple of looser ones upstairs that will need some reinforcement. I don't really want to bite the bullet that you mention!

I still hope to be able to sand and finish the floor to a decent standard. I've made a first pass with the 60gr and with the use of a good work lamp I get a better idea of how well the sanding is going. The abrasives used were Mirka aluminium oxide discs. The finer grades are their mesh type abrasives which hopefully will last a bit longer... It's an old floor that I really don't know what coatings were applied previously. Wax, oil and lacquer have all gone down previously. There is still a bit of inconsistency across the floor in terms of colour after the first pass that is most probably where traces of the previous coating remain. Hopefully after another pass I will find a more consistent base to work from...

Thanks again for the interest Cubist.

Matt

 

[overlander matt]

The swirly grain pattern on the treads looks like Elm. We have Elm treads and risers on the stairs down to our basement. About eighteen years ago I stripped, and oiled them, and they are holding up well to frequent use.
The oil was nothing fancy, just boiled linseed oil let down with white spirit, the same mix that my father used for the wooden floor in his greengrocers shop.

Thanks Stevers. I'm not very familiar with Elm and I've just assumed we have oak on the staircase here. Glad to hear your finish has lasted well - just what is needed!

 

[Cubist]

Hi Matt,
Sorry to hear you've been unwell and nearly as sorry to hear that the boards are only 12mm.

That said, it's clear the builder knew there would be a deflection challenge and tried to eliminate that possibility by setting the joists so close together. Sad too that his strategy seems to have failed but he has me wondering just how he reconciled the height difference between the stair head and the floors surface. Clearly you have a need to get the floor back into a serviceable and aesthetically acceptable condition right now but I think you perhaps shouldn't bother trying to close the gaps right now and 'certainly not' drive in the extant nails. Almost anything you may use to fill the gaps will, in my view, fail in fairly short order and driving those nails run the risk of damaging the boards perhaps beyond repair.

Sadly, I think the best long term strategy would be to lift all the boards and install a sheet material below them and then use an adhesive to re-fix the boards rather than nailing them. This though may be problematic insofar that it introduces a need to reconcile any differnces between the final surface heights of all the floors of surrounding rooms - beware doors that open 'over' the floor. However, it would maybe offer an opportunity to 'flip' the boards to take advantage of a cleaner or otherwise better finish/condition on the current underside.

Good luck and I hope none of this causes you any more pain.
Cheers,
Cubist

 

[overlander matt]

Hi Cubist,

Thanks for the concern! Not feeling too inclined to spend much time on the hands and knees with the sander right now but I'll be back on it again soon!

The situation with the floor boards is maybe not so obvious as I suggested - I had never actually taken the downstairs floorboards up so decided to investigate this a little further as there were a couple of looser boards in the door thresholds that could be looked at. I seem to have some variety, which is good because 12mm was the very thinnest downstairs... In the door threshold I have around 20mm. The thinnest section was around the first diamond that I posted here. The centre part of the diamond was lower than its neighbour which over the years had worn down. The central diamond is 12mm but of varying thickness with a large pile of wood shavings packing it up. We're probably looking at around 15mm minimum away from the central diamond. Having popped a blade in between the boards in places, I will suggest the boards are in the order of 15-18mm downstairs with just the diamond at 12mm. I've subsequently fitted a section of ply underneath the central diamond piece and adjacent dark wood to bring this closer to level.

I think I can work with the downstairs floor as it is, without lifting the boards on this occasion. There won't be any hard gap fillers used and I will follow the waxing rather than lacquering route. There is still quite a lot of sanding to do and hopefully I can get more life out of the abrasives on the second pass. I was planning to work through to 150 or 180gr. Would this be sufficient?

Interestingly, I had removed a few boards upstairs during re-wiring and plumbing work a few years ago. These are definitely thinner than downstairs having investigated more thoroughly and it'll be interesting to see how I get on with that area. There are a couple of boards that feel like they will need additional noggin support. Probably this will be more challenging...

 

[Cubist]

Hi Matt,

De nada. I share your reluctance, easy enough to get down but getting up... well that's a longer story.

Good to know the rest of the floors appear to be of greater depth albeit that there may be some showing similar reductions presumably through wear. The upside of that though is that those showing greater wear are likely to appear in the lines of most likely foot traffic and also suggest great age if one assumes the boards were all uniform in depth when first laid. Are the thin boards you've found upstairs in similar high traffic areas?

Don't give up to quickly on the caulking cotton. Provided you can braid it to be thick enough that there is strong positive resistance when you press it between the boards, and can avoid pushing it right through, it will still do a good job for you. Also, coated with a little linseed oil it will also gain a stronger bond to the sides of the boards. If you do this though, be sure to test the colour first as you may decide to apply a little chocolate paint before the linseed to get a closer match.

Cheers,
Cubist (aka Steve)

 

[overlander matt]

Thanks again Steve!

I've not been looking at the floor this week - there's been another job to progress that is on the realistic 'Done for Christmas' list but needs some attention... The planning on the floor can at least continue though.

I will try out the cotton caulking approach as you have suggested. A flexible filler will be best in our case and this seems to be a good approach. Colouring the cotton will be necessary as you mentioned so I'll have to track down something brown to colour it with.

I'll get an order in shortly for some cotton, some shellac and wax. I'm looking forward to making some progress soon.#

Thanks again!

 

[Cubist]

A tester pot from any local DIY store - Milk Chocolate Brown emulsion.

 

[overlander matt]

A couple of weeks have gone by and I've been back on the floor sanding this week. I have a question about when to stop the sanding - I have been aiming for enough to remove the previous coating but not too much to remove the historic patina that is often spoken about. With a 60gr abrasive, I have made reasonable progress but the discs don't last too long - the hallway floor is tough. The floor colour still looks fairly uneven and some areas are particularly dark still. Using some methylated spirits on a rag has helped highlight where the old floor coating is still present. How much further should I go with the sanding? I wonder how much of the floor colour is related to the timber itself and how much is connected to a previous coating. This is my main dilemma right now - how far to go with the sanding? The plan is to go for a shellac seal and then wax rather than lacquer.



I've had to make some progress on the staircase. We plan to fit a runner and have exposed ends of the treads and risers. Previously these were painted and going further back had stair rods fitted. A quick blast with the sander makes me wonder whether there was a different timber used on the staircase. I think Stevers questioned previously whether this was Elm. What is fairly clear is that the wood on the staircase is much lighter than the hallway and I'm questioning whether I should try a stain on the staircase and landing to give a better match to the hallway. The same questions apply to the staircase about how far to go with the sander. A light sand gives a golden appearance perhaps with some dirt in the grain or go further and the wood appears whiter. There are traces of woodworm in the stairs and the little holes have provided some annoying pores for white paint to sit in which has kept me busy with a sharp point removing these.




The cotton caulking that Cubist recommended should be here soon and I'll apply to the larger gaps.

Hopefully someone can advise on the sanding. Thanks!

 

[Cubist]

With regard to the hall timbers Matt if you're still using it I would be putting that 6inch orbital sander aside and reserving it for the stairs perhaps. I strongly suspect that you are now encountering decades of oil and wax penetration into the hall boards and this is simply clogging the paper. There is a chance too that the heat produced by the sanders friction is 'driving' a lot of that oil even further into the wood. Frankly, given how much timber has already been lost to footfall traffic wear and tear together with previous sanding exercises you are running a considerable risk of the total loss of some of those boards.

In my view you MAY be able to use a palm sander or an oscillating multi-tool sander to focus only on the darker spots in an effort to remove these but I suspect that these will clog too. It would be best I think now to begin focusing on trying to blend the lighter sections of the boards to match the darker sections using a stain or dye. Alternatively, you could try bleaching the darker sections but this requires that the wood is capable of absorbing some moisture which may be difficult if I'm right about the use of oil in the past.

Regarding the stairs. Worm damage is not necessarily a guide but some folk do suggest that some wood munchers prefer elm - Matt Green should be able to advise on that and whether it is indeed elm - but to my eye I think Stevers is right. After you've got rid of the remaining paint from the stairs I would again move to a palm sander as this will be of greater help reaching the outer boundaries of the wood. A uniform grain colour though is again unlikely as no doubt the sides not previously covered by a runner will undoubtedly have been treated with an oil and wax finish finish many times in the past. In terms of a target final colour/shade I think you should take a cue from the hand rails and newel posts and either aim to match these or go for a harder contrast.

 

[overlander matt]

Thank you Steve. I get the feeling I'm not going to lighten the floor much more. There are a few areas needing a little more effort to remove traces of the old coating of lacquer. Ultimately it will be darker than the stairs and landing.

The abrasive is soon dulled after sanding a small area. I'm not sure I observe clogging now but I do. Feel there are areas that historically have been coated with more wax than other areas. The corners are door openings in particular.

Lightening the downstairs may not be easy...

I will look to complete the sanding with a finer grit abrasive. I have a Mylands shellac coating to go down after a dye. What dye to go with is the next decision... I'll investigate further.


Thanks.

 

[a twig]

Bit of a hack but changing the lighting in the room by experimenting with different colour temperatures / filters and Ra values might be the easiest way of lightening the floor

 

[lizziecupcakes]

The cotton caulking that Cubist recommended should be here soon and I'll apply to the larger gaps.

I am really looking forward to learning about your experiences. I will be ordering mine as soon as my loft insulation in and the paper stuck to the floorboards is scraped off