I am intending to use Simpson Strong Tie EB/7070 reinforced angle brackets to anchor the studs to the sole plate in my new garden workshop.

The slab for this is 8m x 6.5m, so it's a bit more than your typical garden shed.

The problem is that I am struggling to establish a suitable fastener to use with the ties. Simpson only recommend a single (and naturally particularly expensive) type of galvanised screw of their own brand (designated the SD10112) and for which I cannot find a UK stockist. (They are available on eBay for around £128 + carriage for 500 but as I am going to need nigh on 2,000 I don't fancy paying this if I can avoid it.)

A conversation with Simpson UK this morning in an attempt to clarify what other fasteners might be suitable has, sadly, left me none the wiser as they (quite typically) are disinclined to offer anything but the very vaguest of possible alternatives.

They did say that I might consider a good quality German screw (Spax for example) as an alternative as the sheer strength of the cheepy screws typically available are distinctly below par but since I was already aware of this it did not help much.

Goggling around has not helped much except to highlight the fact that there are plenty of suppliers of the ties but no suppliers of the recommended screws.

So the question is, assuming that people are not just buying the ties to make into wind chimes or other garden ornaments - which screw are all the purchasers of the ties buying to fix them to their timber and therefore, by extension, fix their building to the slab sufficiently well to avoid it being blown away on a light zephyr?

The recommend screw is billed as a hot dip galvanised hex drive 1.5" #10 and looks more like a mini coachscrew with a good solid old fashioned dowel section to it rather than the more modern narrow necked screws.

I could just get hold of an individual tie and see which screws give me the best fit but this is a bit of a hit and miss approach and I would prefer to have a better guide than my own intuition. Nevertheless, if needs must then this is what I will have to do.

To add to the misery (and hence my nervousness about selected the correct item) the Simpson web site is full of dire warning about corrosion in connection with treated timber and is recommending only hot dip galvanised or stainless (316) fixings as being safe in this context.

Yes - 18mm ply on the inside and 9mm OSB (plus a load of insulation, another layer of 9mm OSB, and battens supporting the rain cladding) on the outside. (Various DPC layers, DPM layers, and VCL layers omitted on the ground of relevance.)

The EB/7070s have been specified by the structural engineer that provided the slab design. He is concerned that the building is very light and so wants to make sure that it is firmly anchored. Not that we are in a high wind area or anything. I know that structural engineers are often maligned for overdoing things, but, as an engineer myself (electronics not structural), I am happy to go the extra mile for the sake of piece of mind.

Plus I want to avoid nails wherever possible. I far prefer the much greater controllability one gets from using screws. (Or maybe it's just that I'm no good with a hammer. :-) )

Shouldn't you talk to your SE before using the specified brackets in a way other than as a the manufacturer specifies?

Yes, the shear load on some nails is superior to that of screws, or, to put it another way, the shear load of some screws is not as good as that of some nails.

This point was the essence of the conversation that I had with Simpson this morning.

Simpson helpfully publish a table detailing equivalences between their screws and various nails.

I don't like nails and I will avoid them if I can.

Ed - if the manufacturer was able to recommend a suitable screw THAT IS AVAILABLE IN THE UK then we would in all probability not be having this conversation.

The objective of my question is to discover what others have used in a similar context. I can then use this information to feed into my decision making process.

At the end of the day there is no way that I will be settling on a solution that puts my new workshop at risk.

If at the end of the day I am forced to use nails then I will resign myself to banging in the best part of 2,000 of the little blighters but in the mean time I seek the counsel of others in case there is an alternative.

Posted By: ealingbadger

Plus I want to avoid nails wherever possible. I far prefer the much greater controllability one gets from using screws. (Or maybe it's just that I'm no good with a hammer. :-) )

If you worried about the control when using nails get 500 of the specified screws so you can locate all the bracket exactly where you want them and then get to grips with a hammer. Those short twist nails are very strong and you would be trying hard to bend them when hitting them in

I find nail guns extremely unwieldy and heavy to manoeuvre and operate but yes, I would certainly want to employ a gun if I had to use nails.

The SE hasn't explicitly specified the fixings, just the brackets. For reasons I have been avoiding going into I have been trying not to bother the SE as he helped me out enormously after falling out big time with the original SE on this project who simply point blank refused to listen to me or the slab contractor and produced an entirely unsuitable design.

Looks like I am going to have to ask him though.

Posted By: ealingbadgerThe SE hasn't explicitly specified the fixings, just the brackets.

Indeed. But the fixings are implicitly specified as what the manufacturer specifies - at least in the eyes of building control, I'd have thought.

I understand about the SE, having a similarly fraught situation myself. Last time I asked something he responded quickly and helpfully but I still feel there''s a limit to his patience. As DJH says, though, it's probably worth asking. It made sense to ask on here first to at least try to come up with a suggestion of your own but as nobody seems to know I'd go back to him before looking furtherr.

Posted By: ealingbadgerThe problem is that I am struggling to establish a suitable fastener to use with the ties. Simpson only recommend a single (and naturally particularly expensive) type of galvanised screw of their own brand (designated the SD10112) and for which I cannot find a UK stockist.

Going back to the beginning, I just bothered to try to look up the manufacturer document but all I've found are:

http://www.strongtie.co.uk/products/reinforced-angle-bracket/264/installation/3
http://pim.simpson.fr/public/download/gb/en/product/264

These both say the same thing, which seems to be a generic 5 mm screw specification rather than a requirement to use a particular product of theirs. So where does the requirement come from?

Incidentally, the documents also specify ring shank nails rather than twist nails, so I suppose a gun could be used.

Posted By: ealingbadgerAnd then there is the issue that they should be hot tip galvanised (none of your BZP here).

I suppose that's another question. Why do the studs need to be treated? I can see some case for the sole plate but surely the studs are not exposed?

But isn't this a well-defined enough specification that doesn't lock you in to a single supplier?

Strongtie:On wood:
* CNA annular ring-shank nails dia. 4.0 x 35 or dia. 4.0 x 50 mm.
* CSA screws dia. 5.0 x 35 mm or CSA screws dia. 5.0 x 40 mm.
* Bolts.
* LAG screws.

Over the last 24 hours or so I had drafted and fired off (or so I thought) half a dozen emails to various merchants asking pertinent questions on this subject.

Curious as to why I had not received even a single answer (not even an automated response) I checked into the matter only to discover that Outlook had thoughtfully not actually been sending them on account of a pending Windows update.

One reboot later and Outlook duly flushed it's outbox.

Driven to despair I finally did actually ask the SE for his opinion and this was his quick as a flash response:

"Just use a standard 5 or 6mm wood screw from B&Q. Length to be no greater than 75% depth of the timber being fixed into, so 50mm thick timber use 40mm long screw."

So there you have it - I've been worrying about nothing all this time!

I have asked a supplementary about the Simpson corrosion warnings and await his further response.

Posted By: ealingbadger"Length to be no greater than 75% depth of the timber being fixed into, so 50mm thick timber use 40mm long screw"

50 mm x 75% = 37.5 mm max. And if it's actually 47 mm or even 45 mm = 33.75 mm. So even 35 mm screws might be pushing it if the 75% limit was actually to be taken seriously. A scientist, an engineer and a mathematician went into a room ...

I'm not sure what the issue is with corrosion. Just buy galvanized or stainless screws and be done with it.

Plus one on ringi's question.

djh - no, I'm not sure what the issue is with corrosion either but Simpson make a big deal of it. Maybe it is only an issue with the chemicals used to treat timber in the USA... who knows? I've certainly never heard of it before.

Posted By: djh

Posted By: ealingbadger"Length to be no greater than 75% depth of the timber being fixed into, so 50mm thick timber use 40mm long screw"

50 mm x 75% = 37.5 mm max. And if it's actually 47 mm or even 45 mm = 33.75 mm. So even 35 mm screws might be pushing it if the 75% limit was actually to be taken seriously. A scientist, an engineer and a mathematician went into a room ...

Plus one on ringi's question.

You are neglecting the thickness of the bracket itself. :-)

Actually, to be fair to the SE with his recommendation of "...50mm thick timber use 40mm long screw" he is most certainly on the pragmatic engineering side of the equation.

ringi - the brackets are as advised by the SE. Personally, I'm happy with that although I appreciate that many times people don't use them. My 'shed' is a bit bigger than the average (although still quite a bit smaller than a house of course).

Paul - yes, I was nervous about that after reading the apocalyptic warnings about it on the Simpson site but I am reassured that my SE does not rate it as an issue here in the UK.

Using my good cordless screw driver (that I already own) it is a lot quicker to put in screws then I could ever put nails in my hand. Nail guns are still not in most peoples tool boxes.

Posted By: ealingbadger


The Tek screw from Screwfix that Beau pointed out seems promising... if it were not for the prospect of having to remove 2,000 washers by hand!

Did a little play with some Tek roofing screws yesterday and the washer comes off very easily. Just put impact driver into revers and hold washer and 2 secs and it's off. Not sure what brand they were as they came with some roofing sheets.