I've built several decks and platforms in boards that have no grooves (UK Larch and Oak) because I prefer the appearance of the boards and because they are UK sourced and need no chemical treatment. The downside is that there is, I assume, a greater chance of slipping, especially when wet.
Options appear to be use grip strips (several variations available), at least on the steps and leading edges, or a treatment that contains fine sand. I have tried a product called 'Deckgrip' which is an oil (or varnish?) containing fine particles and it certainly is grippy, almost abrasive under bare feet, but after less than 1 year of traffic and weathering the finish was flaking off leaving a very ugly deck.
Has anyone had any experience of a more durable finish for timber that will serve the non slip purpose?
Karl, wow, it sounds like you've done a thesis on timber and slippage. Thanks for the lengthy suggestions.
I'd never heard of a slip rating nor TRADA. I do know about the non slip strips but only consider them for steps. I'm not about to resort to grooved timber only to protect me from possible claims by litigious customers who go ass over tit on a structure I've installed and they've not maintained.
I also know how slippy grooved boards can be when dirty and wet.
Karl Harrison said:
The best way to keep your deck at its best is regular cleaning and quality decking oil, stay away from nonslip chemicals or if you are in a commercial set up use carborundum strips that are DDA compliant and have a slip rating of 57 wet and 65 dry
If you consider a smooth piece of timber for an exterior application; also consider a foot placed upon it. If the surface is smooth then maximum friction will apply and the slip resistance will be high and thus slip potential will be low. (We have slip tested a piece of Elondo and the mean results were 63 wet and dry combined, this was smooth decking.)
Now consider exterior timber with either ribbed or a grooved finish. Now the foot contact area has been massively reduced by as much as 95% (ribbed finish refers) this has now reduced the friction and in turn has high potential for slip.
These statements have been based on clean and new decking, not old unmaintained timber.
Other issues with grooved or ribbed deck is that when wet they do attract dirt, dust and pollen. When dry (it takes this grooved style of deck twice as long to dry) this dirt will now form a base for algae and moss to grow.
The grooved deck will take longer to dry out due to the increased surface area will cause the timber to absorb more water. To consider this in more detail read up on transpirations rates of timber. Basically the timber will absorb quicker that the water can evaporate.
Having spoken at length to TRADA, they are now considering changing their views on decking and how grooves and over machining is detrimental to the timber and the user.
Cutting/routing in grooves will only allow water to sit unless they go all the way through the board allowing water to drain away.
With respect to anti-slip chemicals, they can’t be used commercially. In short they are only warranted for what is in the tin and as soon as you apply the product the warranty is void. This is due to the amount of unknowns – how much is applied and how often, how often the deck is cleaned, volume of foot traffic and the weather – UV and rain.
To keep a smooth deck looking good and to ensure longevity, keep clean, keep oiled
Owatrol products are worth a look for maintenance and oil.