Green Building Forum - Too many bolts Thu, 16 Apr 2026 19:10:55 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308559#Comment_308559 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308559#Comment_308559 Sat, 14 Jun 2025 21:40:29 +0100 tony https://share.icloud.com/photos/0a0VoDHfDyzthn84VYO6y3FnQ

Why so many bolts?]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308560#Comment_308560 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308560#Comment_308560 Sat, 14 Jun 2025 21:48:00 +0100 Nick Parsons Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308565#Comment_308565 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308565#Comment_308565 Sun, 15 Jun 2025 08:09:40 +0100 fostertom
Maybe because they're unusually small bolts - usually in this type of application you get say three fat 18 or 20mm bolts, usually in incredibly slack holes. Maybe the Engineer is aware to spread the considerable rotational load into the timber with multiple tighter-fitting bolts over the full contact area.

See how, on the adjoining rafter ends, it looks like that rotation has happened anyway, the ridge has sagged/dropped, the rafter pitch has flattened, considerably.

I like the stop-chamfer on each rafter under-arris. If using planed timber, this kind of detail makes a huge difference - as carpenters knew routinely till early-20C. The 'modern' eco-aesthetic is to use rough-sawn timbers instead, which in my experience works fine as green unseasoned - cut the doug fir one day, saw it the next, nail it up the day after, no green-stain 'presertvative', no shipping round the world, no stockpiling at the builders merchant - why isn't it cheaper by far?

Hey, suddenly twice in a row (and a third experimental time) I'm getting fostertom auto-filled into the Whisper box, so it gets Whisper/messaged to me. Anyone else?]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308568#Comment_308568 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308568#Comment_308568 Sun, 15 Jun 2025 11:26:28 +0100 djh Posted By: fostertomHey, suddenly twice in a row (and a third experimental time) I'm getting fostertom auto-filled into the Whisper box, so it gets Whisper/messaged to me. Anyone else?Yes, I'd noticed that, and been very annoyed by it! I expect somebody's changed something they thought was minor. It doesn't coincide with any change in anything at my end.]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308569#Comment_308569 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308569#Comment_308569 Sun, 15 Jun 2025 11:28:58 +0100 djh Posted By: tonyWhy so many bolts?Same reason there's so many nails in a nail plate? Whatever that is. Bolts aren't used often in positions where they're shear-loaded I think, and have to be specially rated to be so used. Maybe the shear loads are large?]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308620#Comment_308620 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308620#Comment_308620 Tue, 17 Jun 2025 21:35:14 +0100 tony Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308637#Comment_308637 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308637#Comment_308637 Wed, 18 Jun 2025 20:35:08 +0100 fostertom Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308644#Comment_308644 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308644#Comment_308644 Thu, 19 Jun 2025 22:16:11 +0100 Rex Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308645#Comment_308645 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308645#Comment_308645 Fri, 20 Jun 2025 08:45:01 +0100 revor
Posted By: djhSame reason there's so many nails in a nail plate?


The nails used in these situations are square twisted nails jobbing builders eraneously use galvanised nails]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308646#Comment_308646 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308646#Comment_308646 Fri, 20 Jun 2025 10:44:55 +0100 Peter_in_Hungary Posted By: revor
Posted By: djhSame reason there's so many nails in a nail plate?


The nails used in these situations are square twisted nails jobbing builders eraneously use galvanised nails
Two types of nail plates AFAIK are the nail plates made by pressing spikes out of a galv. plate which can only successfully put in with a press which for a good job limits them to factory type assembly, the other type is a plate full holes, good for on site construction and for these I always use screws but for nailing either twist nails or ribbed nails would do but I find screws quicker. (I don't have a nail gun)]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308647#Comment_308647 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308647#Comment_308647 Fri, 20 Jun 2025 10:50:06 +0100 WillInAberdeen
In the example of a nail plate, you could imagine removing all the nails and replacing with a super sized G-clamp to clamp the plate hard against the timber. The G clamp has no shear strength itself, but the clamping friction means the timber cannot slide out past the plate and the truss would stand up. The nails or bolts are driven or tightened to a high tension to give the clamping effect.

Bolt holes are sometimes made over sized so the sides of the bolt don't touch the material and there's no shear force on the bolt, only tension.]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308648#Comment_308648 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308648#Comment_308648 Fri, 20 Jun 2025 11:36:48 +0100 Peter_in_Hungary
Another concern is that with todays timber (here at least) there will always be shrinkage because the timber is not properly seasoned. This shrinkage can loosen the plates so that friction in lost and shear on the fixings can result.]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308651#Comment_308651 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308651#Comment_308651 Fri, 20 Jun 2025 13:17:07 +0100 fostertom Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308654#Comment_308654 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308654#Comment_308654 Fri, 20 Jun 2025 18:20:55 +0100 djh Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308666#Comment_308666 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308666#Comment_308666 Sat, 21 Jun 2025 15:52:00 +0100 WillInAberdeen
Find a smooth shiny wire nail and knock it into a piece of wood. Now pull it out again with your fingertips.

It won't come?

That's because of the friction of the wood fibres, even against the smooth steel surface.

Now try again with a Victorian nail in a roof?

Nope, still won't come out, even after 150 years seasoning and oxidation .

Friction is why buildings stand up, it's vastly under rated!]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308667#Comment_308667 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308667#Comment_308667 Sat, 21 Jun 2025 18:29:42 +0100 djh Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308668#Comment_308668 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308668#Comment_308668 Sat, 21 Jun 2025 19:54:41 +0100 revor Posted By: Peter_in_Hungarythe other type is a plate full holes, good for on site construction and for these I always use screws but for nailing either twist nails or ribbed nails would do but I find screws quicker. (I don't have a nail gun)

Screws are unsuitable they are already weakened by the thread and the plate holes sit in the thread so you have a point load. I helped a friend build his house and he had problems when fixing I beam rafters to the ridge. Many of the screws broke as the structure moved. They were qualiity SPAX countersunk screws and they broke the head off. Perhaps pan heads would have been better more surface contact bearing on the plate. When I built my roof sq twist nails were specified and the BCO checked that I had used them.I did use screws to prefix timbers in position as that was easier than trying to hold timber and plates in place whilst holding hammer and nail. Once couple of screws in place reverted to nails then swapped the screws for nails. BCO spent an awful amount of time checking the tinbers were correctly braced and straps in place. Being in an exposed area think that was the reason. If you make a mistake with sq twist nails they are one hell of job to get them out.]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308669#Comment_308669 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308669#Comment_308669 Sat, 21 Jun 2025 20:16:33 +0100 djh Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308672#Comment_308672 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308672#Comment_308672 Sat, 21 Jun 2025 23:15:11 +0100 Peter_in_Hungary Posted By: revor
Posted By: Peter_in_Hungarythe other type is a plate full holes, good for on site construction and for these I always use screws but for nailing either twist nails or ribbed nails would do but I find screws quicker. (I don't have a nail gun)


Screws are unsuitable they are already weakened by the thread and the plate holes sit in the thread so you have a point load. I helped a friend build his house and he had problems when fixing I beam rafters to the ridge. Many of the screws broke as the structure moved.
The screws I use are rated for structural use. they don't have countersunk heads but rather flat head with the thread stopping before the head. They are put in with a torx bit. A bit like e.g.
https://www.screwfix.com/p/fastenmaster-headlok-spider-drive-flat-self-drilling-structural-timber-screws-6-3mm-x-70mm-50-pack/378pp]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308673#Comment_308673 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308673#Comment_308673 Sun, 22 Jun 2025 07:27:54 +0100 revor Posted By: Peter_in_Hungaryhttps://www.screwfix.com/p/fastenmaster-headlok-spider-drive-flat-self-drilling-structural-timber-screws-6-3mm-x-70mm-50-pack/378pp

Thanks for that.

Did not know of these they look a really decent fixing. Could have used these instead of.

https://eshop.wurth.co.uk/Product-categories/ASSY-4-WH-steel-zinc-plated-PT-washer-head-RW/31083508071325.cyid/3108.cgid/en/GB/GBP/?CampaignName=CS008&RecoId=categorytopseller%40categorypageA

Which I used to fix window brackets for some very large windows.]]> Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308674#Comment_308674 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308674#Comment_308674 Sun, 22 Jun 2025 10:37:44 +0100 djh Too many bolts https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308681#Comment_308681 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18303&Focus=308681#Comment_308681 Sun, 22 Jun 2025 15:06:08 +0100 Peter_in_Hungary Posted By: djhPiH, those screws are structural-rated so OK on that front. That's an important qualification. But they look to be rather larger diameter than the holes in any nail plate I've seen?
I did say
Posted By: Peter_in_HungaryA bit like e.g.

The ones I use are a good fit for the plates available here]]>