I began my intended garage layout in late Summer/Autumn last year, and only got as far as building the baseboard, which is a 'U' shape in the rear half of my double length/width garage, utilising 9mm ply. Unfortunately I didn't then get around to sealing the bare ply before the onset of winter, and my garage is no place for spending time in during freezing weather, so it got left. As Winter progressed, the baseboard, or at least most of it, began to turn black with mould, not actually 'growing', but quite badly staining the ply, due to the inherent dampness in the UK climate. Until the weather began to improve, there was little point in attempting cleaning as it would just repeat the mould process, so I left it as it was until yesterday morning, when I made a start on getting it sorted. First job was to clean off/kill the mould, so a strong bleach and water solution was applied with a cloth, followed by a further wipe down with a fresh cloth and clean water. This improved things, though still left some dark marks in the ply, but at least I had the basis for a start on sealing the ply. Leaving the garage doors wide open for a couple of hours quickly dried the ply ready for the paint. During the Winter, I'd researched products suitable for sealing the ply, and it seemed that professional decorators swear by a paint product called "Zinsser B-I-N", which is a primer/sealer used for walls/ceilings etc which have been watermark stained, as anyone who's had that happen will know that umpteen coats of 'normal' paint can be applied and the stain will often reappear. It's not a paint like most others as it's Shellac based, pongs a bit since it seems it has a 'Meths' content (which is the recommended brush cleaner), and is white in colour. Since it has a Meths content, it dries in about 20 minutes and is recoatable in 45 minutes, so I was able to get 2 full coats on in the afternoon, leaving a really nice smooth clean surface to which I shall now be able to apply an oil based final coat of a brown earth coloured paint ready for some tracklaying to begin in due course. A 1 litre tin of this Zinsser isn't cheap (£18.53 at Toolstation, £1 cheaper than Screwfix) but given it's reputation amongst decorators, it'll be worth it and hopefully I can now make progress with the layout. Keith.
Just to be pedantic, I would suggest that it is closer to a sealer/varnish than paint. The great thing about Shellac is that each coat dissolves the previous, and mixes in, that's why you get such a deep shine with French Polishing, which is mainly Shellac, also known as Button Polish, and because it keeps doing that as you add coats, you don't the usual problem that paint causes, which is thickness, that builds up with each subsequent coat.
Must have been a big relief that it was fixable, and seemingly quite easily. I've tried without much success to cover a couple of annoying watermarks on one of my ceilings, mistakenly as it turns out with one of the cheapest sealers I could find, so probably time I give this Zinsser a go
Zinsser primer stain blocker is a good product which I have used in the past on clients projects... but as suggested is expensive to buy, it will cover watermarks on ceilings and walls caused by either plumbing leaks or damp effervescence which is best treated with an antifungicidal wash. One little trick to share with home repair jobs when it comes to eradicating salt marks in plaster is to use an oil based undercoat brushed forabout 40mm beyond the stain parameter, leave to dry for 24 hours and the lightly abrade with either a scratch pad or 240 flatting paper, this gives a good key for the first coat of acrylic vinyl emulsion to grab to... you wont see any "stepped edges" glinting through the final finish coats if a decent Purdy or Hamilton Perfection Plus brush has been used for the undercoat base stain blocker. Again its all down to whatever return of finish is desired ... using cheapo paint and brushes won't save you any money long term it just leaves a less than desirable finish.
The hardest part these days is actually finding a decent oil based paint, most 'paints' these days are of the 'Wash your brush out in water' type and absolute rubbish. Since the banning of lead based paints it seems quality has gone downhill (though prices have gone upwards!) and to be honest I find the excuse that it was harmful to children hard to take, certainly my 3 kids never sucked or licked skirting boards or window ledges, and I myself worked on a lead smelter plant for 18 months and I'm still sane (though all things are relative!!! ). This is the result after the 2 primer coats.
The oil based paint I eventually found for the 2 top coats was Sandtex "Autumn Chestnut" satin finish as I don't want shiny soil. Any area's that don't eventually have grass, ballast or road surface will show through as just soil. This pic was taken after the second coat was applied and is still wet, hence the shine. Soon be ready for some tracklaying. Keith.
This is an offcut of the ply I had left from the baseboards, and was stored on the beams of my garage above the baseboards. As can be seen, this was similarly affected by the mould so you can see why I had to sort it before beginning tracklaying. Keith.
Unlikely to work on such a large invasion, but I've found that occasional small patches of mould, which I sometimes get in the bathroom, are quite easily removed by covering them with an anti-bacterial wipe for c24hours. Seems to fix it for 4-5 months.
