Sunday, 17 August 2008

Refinishing wooden floors on the cheap

Sanding wooden floors is a pain. If I had it, I'd gladly pay £40 per square metre that professionals charge for sanding, filling and lacquering wooden floors.

After years of procrastinating, I've finally tackled the three upstairs bedrooms of my Victorian semi. That's about 300 square feet. After three days, it's one down and two to go.

Three years ago I did the whole ground floor. A few years before that a studio flat with parquet floors. After much sweat and tears they came out fantastic, so I think I know a bit about floor sanding and, at your own risk, I can share with you some tips I've learned the hard way.

Unless the boards are pristine condition and all you want to do is brighten up some old grey boards that have lain under lino or carpet for a few decades, floor sanding will take a lot of time. More time than you probably have and if you think you can do three bedrooms in a weekend, dream on. If the boards have been stained or had tiles glued on them, double whatever number you first thought of.

Which is why my top tip is don't bother hiring a floor sander/edge sander package for about £80 for a weekend.

The big drum sanders or orbitals are great when the floorboards are level and and true and sit flush next to each which might be the case when refinishing a basketball court or dance floor but not my house!

The big drum buffs up the high points just lovely but they can't get it into the dips caused when old boards shrink and buckle according to the direction of the grain. I found that I used the edge sander for most of the floor because of that. I used a £30 machine to to do 90% of the job while a £50 machine sat unused.

With the rental clock ticking, the temptation is to rush the job and piss off your neighbours by sanding late into the evening. Plus, although the sanding belts are on sale or return, the prices you pay for the expendables from the hire shops are double what you'll pay at trade prices.

If you want to be cheap, you can do what I've done and buy a good angle grinder for about £30 with a sanding disc attachment and buy lots of boxes of paper discs for about £11 per box of 25. You get through a lot of discs but this costs less than the machine hire and with your own tools, you can work at your own pace.

When using a disc sander on the floor, you will be working close to the sharp end of the tool and so you must wear a mask and gloves and eye protection. Some kneepads are a really good idea too.

Warning: if you hit a nail with the sanding disc, the grinder will jump out of your hands.

ALWAYS run a dry sponge or cloth over the floor before you start to catch any protruding nails or tacks. If the floor was ever carpeted, there will be some tacks in it. A flying sanding disc at 1100 rpm cuts flesh like butter. Or even the flex and leaves really deep gouges.

One problem with wearing eye protection or glasses is that they fog up when you also wear a paper dust mask. Exhaled breath flows out the sides of the mask at the bridge of the nose and fogs the lenses.

At this, most people either chuck off the mask or the eye protection but either choice is hazardous to your health. My solution is to tape the mask across the bridge of my nose with surgical tape or sticking plaster. This prevents the exhaled air from condensing on the lenses.

postscript: I have realised the dust masks pictured are not up to the job. I had to wear two at a time. There are much better masks with valves and seals to prevent fogging that cost around £1.80 each. YOUR LUNGS ARE WORTH IT.

I start by stripping off any stain or glue with a 36 grit disc (on right). When the board is clean, I go over again with a 80 grit disc (on left) to finish.

For a 10' x 10' room with a painted floor, I have generally used about 30-40 rough discs for cleaning and 3-4 fine discs to finish.

Without stain or paint on the floor, one disc will last about 20 square feet. With stain or paint, I am lucky to get 2.5 ft sq cleaned up with a 36 grit.

The rough discs clog quickly on paint or stain. You have to stop every five minutes or so to change discs but hey, you're still saving money!

If you use a clogged disk for too long, it just burns the wood.

When you stop to change the discs, vacuum up the dust as you go. It's a really good idea to seal the doors to each room with plastic tarps or painter's cloths.

A Henry will be very useful. I used to swear by my Dyson but one day it caught fire after sucking up lots of brick dust but our Henry that replaced it never complains. Also, there's nothing on a Henry that can break that costs £40 to replace.

On the right are some boards with a black stain applied in the 1970's when black floors were fashionable.

Cleaning one quarter of the room took about 3 hours on my hands and knees.

It's a pain working on your knees but you are at least aware of how good a finish you are getting.

With practise, you can feel the disc working the wood and will be able to strip the paint off without scoring the wood too deep.

When the boards are cleaned, you can finish off any rough bits with a orbital sander, these cost about £15. The sandpaper on the roll is handier than the sheets.

You should also lightly sand the first coat of sealer with a fine grade as the first coat will raise the grain of the wood. A good finish is down to good preparation and not the material applied.

When you start out with very old, warped and painted boards you aren't going to get perfectly flat ones when you finish (unless you pull them all up and run them through a planer). Putting on the acrylic, you can see the cupping that a disc sander makes but when the acrylic is dry, you don't notice it and given the age and warps of the boards, it looks natural anyway.

Acrylics are hard wearing and are easy to apply and clean up. I regret my Danish oil experiment.

I've used a variety of floor sealers and Rustin's is as good as any other and Coopers, my local hardware store, actually has it cheaper in-store than I can find it online. I'd also recommend Cuprinol's Bourne Seal

Acylics can be walked upon after 20 minutes (but leave it 24 hours before putting back the furniture). Three coats can be done in about two hours with a sanding in-between.

1 comment:

  1. Fabulous, wonderful clear advice - cheers Nat!