Warning for Biltema's decking screw

[Harald Blåtumme]

Haven't had any problems with Biltema's stainless decking screws (A2) at least. Fairly soft steel quality and unlikely to break due to movements in the wood. Quite soft in the head as well, but for the purpose of screwing decking, the strength in the Torx is sufficient, I think. But yes, we've broken a few screws during assembly as they can't handle just anything.

Some sections of the frame were screwed with coarser 6 mm outdoor wood screws C4 from Biltema 120-140 mm T-25 Torx and in a much harder steel quality, which also worked excellently over time. Different story with their anchor screws in fittings, absolutely no problems; rather, I would say they are extremely strong screws. Have only used standard powerful screwdrivers and not impact drivers.

I would advise against using screws made of super hard steel in constructions that move, like decking, whether they're from Biltema or another manufacturer.

Sorry for quoting myself, but I just built a slightly smaller deck, around 2500 Biltema RF A2 screws in various lengths 55 & 75 mm were used, leftover from a previous build, plus coarser steel screws like "BigDog" 8-10 mm in 50-120 mm length (not Biltema).

Biltema's relatively soft stainless decking screws were mostly driven on the middle setting 2 of 3 (about 120 Nm) with my Milwaukee M12 FIWF12 impact wrench with a hex adapter. Indeed, you never actually reach those torque levels - the screw usually bottoms out without impact, then you give a few gentle taps at low speed to get it to the right level. Quick screwing without pre-drilling, no broken screws, and only one bit used without visible wear.

The coarse FAST Big Dog screws were driven at full power around 340 Nm in T40, with no problems at all and super fast to screw in. A lot better than French wood screws, which were used more sparingly. Haven't tested Biltema's equivalent, but here it's probably mostly the bits that get tested, and believe it or not - I used Biltema bits from a cheap screwdriver set.

 

[kortis]

My Biltema screws snapped only when the wood swelled during the winter

 

[Harald Blåtumme]

The first deck we built was with Biltema's A2 stainless steel, around 2014. No screws have broken, even after removing and reinstalling several decking boards due to work under the deck - no problems at all. The screws left over from that build were what I used this summer for the smaller project. How today's Biltema screws perform, I do not know.