First Floor: wall plates, hangers and joists - connecting up

[MikeSharp01]

24 minutes ago, recoveringacademic said:

M12 is about double the diameter of any coach bolts I've seen. But I note the architect's reference to SE and Durisol approval. Had you not written your post @JSHarris, I would have missed that. Thanks indeed.

Very True although its a balance think but as long as your studding is as large in diameter as the specified bolts, and approaching the width of the plate you should be fine.

[MikeSharp01]

13 minutes ago, Onoff said:

I think some of that studding from the sheds is only Grade 4.6 mild steel. Years back we BINNED all our 4.6 stuff and from thereon in only ever use 8.8 min. The 4.6...well you can tell the difference when you hacksaw or file it it's so soft.

Just run the stuff you have past the SE and all will be well.

 

 

[joe90]

When you get to do the actual flooring look at 22mm "easy peel, moisture proof chipboard". our builder always uses it and glues it with D4 glue to the joists and between sheets , no nails or screws. Ours was put in when the brick/blockwork was at first floor level and it got soaked during the rest of the build but remained intact with no water damage. I am not pealing the surface plastic  off till after the plastering and the flooring has remained really clean. cannot recomend it enough.

[ToughButterCup]

Yes, @joe90, thanks. Someone had mentioned that to me earlier this month, but I had forgotten it. So thanks for the nudge.

[Alexphd1]

52 minutes ago, joe90 said:

When you get to do the actual flooring look at 22mm "easy peel, moisture proof chipboard". our builder always uses it and glues it with D4 glue to the joists and between sheets , no nails or screws. Ours was put in when the brick/blockwork was at first floor level and it got soaked during the rest of the build but remained intact with no water damage. I am not pealing the surface plastic  off till after the plastering and the flooring has remained really clean. cannot recomend it enough.

 

That sounds just like what we are looking for next, is it the caberdek stuff?

 

[joe90]

Yep, that's the stuff, the dogs doodads ( in my opinion). Our builder has had several inches of water standing on previous floors for days with no damage. I like the peel off protection, better than scraping plaster etc before decorating, carpeting.

Edited September 21, 2017 by joe90
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[PeterW]

I've got the grey Egger P5 and it's has an inch of water stood on it with no ill effects. Was open to the elements for 10 weeks and was fine. I wanted the peel off stuff but the merchant didn't stock it and the grey painted stuff was just as good. 

 

Stuck down with D4 and it's solid .... 

[Construction Channel]

well, it seems I'm late to this one as always.

 

the self-tapping coach bolts I think he is referring to will be these (called thunderbolts round our way, great name)

http://www.ebay.co.uk/itm/M6-M8-M10-M12-M16-HEX-HEAD-MULTI-FIX-THUNDER-CONCRETE-BOLTS-SCREW-ANCHOR-FIXINGS-/112336280362

you may already have the bar but the resin isnt cheap, and it is a lot more labour intensive to put in so may be worth considering just buying what was specced,

 

as Russel said be aware that you want "jiffy hangers" not masonry hangers for this application, also they come in many different sizes e.g for 2" wood they come in both 50mm or 47mm so make sure you get ones for the finished size of your joists, they also come in long and short leg versions, for a 200mm plate I would suggest getting short legs as when they wrap over the top of the plate it becomes an issue for the flooring, also these "should" be fitted with min 30mm twist nails (my least favourite job) but I would recommend 40mm as you will hit your fingers less.

 

IMO the grey egger Peter used is a better product than the peel clean stuff if you are intending for it to get wet, 

https://www.egger.com/shop/en_GB//PROTECT-EGGER-Protect/p/PROTECT

https://www.egger.com/shop/en_GB//PEELCLEANXTRA-EGGER-Peel-Clean-Xtra/p/PEELCLEANXTRA

yes glued on both joints and joists, but I cant see the advantage of not screwing it down also but each to their own,

 

I am a little confused about the airtightness bit, how are you planning to make the rest of the wall airtight? 

[Alexphd1]

anybody whisper a guide price for the 22mm carbadek stuff.

[Jeremy Harris]

The bearing stress thing is very often forgotten about, but is 99% of the time more critical in shear than the fastener.  An example:

 

Take a 10mm plain shank bolt of ordinary mild steel (the cheapo stuff with a max allowable single shear stress of around 60 N/mm², something like AISI 1010).  Let's say we're using this to bolt a bit of 50mm thick timber to a wall, and the timber is, say C16, with a max allowable bearing stress of around 1.8 N/mm².  Ignoring the small contribution from the wall to timber friction, let's look at what the bolt will take versus what the timber will take, in terms of max allowable load (no safety factor here, so reduce these values by AT LEAST 1/3rd for a real design):

 

The bolt bears on an area of the timber that is equivalent to the bolt diameter x the timber thickness, so in this case 10mm x 50mm = 500mm².

 

The bolt max allowable load in single shear is the cross sectional area of the bolt x the max allowable shear stress, so 3.14159 x 5mm² x 60 N/mm² = 4712 N

 

The timber max allowable load based on the bearing stress limit = 500mm² x 1.8 N/mm² = 900 N

 

So, even the very crappiest bolts you can find will be at least 5 times stronger than the hole in the timber, so that is factor that is limiting the max load.

 

This is almost always the case with construction, it is really rare to find that the fastener strength is the limiting factor, it's almost always the bearing stress in the hole that limits the max load.

 

Edited September 21, 2017 by JSHarris

[NSS]

Ian, i've not read all this thread, and have not yet had a chance to check all the odds and sods I have left over, but I know have quite a few joist hangers if you want them.

[ToughButterCup]

19 minutes ago, JSHarris said:

[...]

it is really rare to find that the fastener strength is the limiting factor, it's almost always the bearing stress in the hole that limits the max load.

 

Right then. Time for a brief discussion with the SE and Durisol with your post to hand so I can sound as if I know what I'm on about...

 

14 minutes ago, NSS said:

Ian, i've not read all this thread, and have not yet had a chance to check all the odds and sods I have left over, but I know have quite a few joist hangers if you want them.

 

Mindful of @Construction Channel's very informative post, I'll give you a nudge if I may, please.

Ian

[ToughButterCup]

1 hour ago, Construction Channel said:

[...]  I am a little confused about the airtightness bit, how are you planning to make the rest of the wall airtight? 

 

Here's too much detail.  But worth the read.

[ToughButterCup]

1 hour ago, Construction Channel said:

[...]

I would suggest getting short legs as when they wrap over the top of the plate it becomes an issue for the flooring, also these "should" be fitted with min 30mm twist nails (my least favourite job) but I would recommend 40mm as you will hit your fingers less.

[...]

 

Why?

[Construction Channel]

2 minutes ago, recoveringacademic said:

 

Why?

Dunno really. That's just what it has printed on the Simpson version we buy. I have seen a few people useing screws but our bco isn't a fan of that unless it's in a place you can't swing a hammer. I assume it has things to do with shear strength but I'm sure other people on here could give a more informed opinion. 

 

Re: the airtightness I checked that thread just after I posted. Whatever you put in is going to make a hole in the S+C slurry (assuming that is the plan). I can't see it being that much of a problem. If you really wanted you could put a dollop of CT1/fix all in the hole before you wind the bolt in and/or stick some tape over the bolt head. The advantage of the thunderbolts being "self tapping" is they should be pretty bloody tight in the hole. 

[bassanclan]

Maybe I'm misunderstanding things, but threaded bar and resin etc is going to be a long slow job compared to say concrete screws,   https://www.toolstation.com/shop/p12879?mkwid=sckRtJFKF_dc&pcrid=142501343890&pkw=&pmt=&product=12879&gclid=CjwKCAjwxo3OBRBpEiwAS7X62RR76LR5

 

or the self tapping coach scrwe/bolts mentioned

[Construction Channel]

52 minutes ago, bassanclan said:

Maybe I'm misunderstanding things, but threaded bar and resin etc is going to be a long slow job compared to say concrete screws,   https://www.toolstation.com/shop/p12879?mkwid=sckRtJFKF_dc&pcrid=142501343890&pkw=&pmt=&product=12879&gclid=CjwKCAjwxo3OBRBpEiwAS7X62RR76LR5

 

or the self tapping coach scrwe/bolts mentioned

Essentially yes. What you linked are the screw version of the bolts he has been specked to use. Slightly different application but the principal is the same. 

 

The question is whether the cost of Ian already having the bar and the resin creating some kind of a "seal" out weighs the ease of using thunder bolts and the questionable difference it will make in "airtightness". 

[NSS]

2 hours ago, recoveringacademic said:

 

Right then. Time for a brief discussion with the SE and Durisol with your post to hand so I can sound as if I know what I'm on about...

 

 

Mindful of @Construction Channel's very informative post, I'll give you a nudge if I may, please.

Ian

Okay, I'll see if I can dig them out tomorrow, take a pic or two and measure.

[Ferdinand]

19 hours ago, recoveringacademic said:

 

Durisol is 65% air. Bit like a bird's bone structure.

 

For information - is this 65% post pour, and is it based on wall volume, block volume, or just the content of the 'shredded wheat' part of the block, ignoring the void which fills fully with concrete?

 

I would love to see a cross section of a post-pour Durisol block, but have not been able to find one.

 

F

 

Edited September 22, 2017 by Ferdinand

[Ferdinand]

@recoveringacademic I have a couple of concerns about using concrete screwbolts in Durisol, and possibly the cost.

 

I have used the hex-headed screwbolt on a number of occasions, eg to fix a wallplate for a conservatory roof onto brick or for fixing bolt down "post supports" for fence posts to a slab, American-style. 

 

Questions:

 

1 - Gripping Strength into Durisol, and size of hole

 

ISTM that these (and concrete screws) rely on a really tight fix to the hard material - brick or concrete) where they are screwed. I am told (not sure that I have always done it) that Thunderbolts are put into a slightly smaller hole (eg M12 into 10mm hole), and the thread is self-tapped.

 

In my experience just a hole 1/2mm too large will make a concrete screw much weaker, so is the concrete infilled matrix of Durisol strong enough everywhere for these to be put in anywhere? I have not done a test with Thunderbolts.

 

I can see that fixing into the solid concrete in the Durisol voids would be suitable, however that could mean 30mm long Screwbolts, which could add quite a bit to the cost.

 

Perhaps one to check.

 

2 - Cost.

 

It is dead easy to end up paying 70p-£1 each for these, as prices are highly variable. Mine have usually cost more than the wood in toto, but I am probably being cautious on the number used.

 

There are a couple of alternative brands to Thunderbolt available. One is called Lightning Bolts (same manufacturer?), De Walt do a range, and Screwfix have a product called "Easyfix". I usually use the Screwfix one, but no longer (unless I wangle that Trade Account and it applies):

 

Have a talk to a company called Bapp Industrial Supplies who style themselves "The Largest Independent Fastener Stockist in the UK". @PeterW and others I know swear by them, but I only found out recently. They have a Preston branch. Just talked to them about Thunderbolts and their price is £45 per 100 for M12 x 100mm bolts, which go in a 10mm hole.

 

3 - If using these for mounting a wallplate I also get some large washers to prevent it sinking into the wood - say 2-3 times the screw diameter.

 

Ferdinand

Edited September 22, 2017 by Ferdinand

[ToughButterCup]

5 minutes ago, Ferdinand said:

@recoveringacademic I have a couple of concerns about using concrete screwbolts in Durisol, and possibly the cost.

[...]

I can see that fixing into the solid concrete in the Durisol voids would be suitable, however that could mean 30mm long Screwbolts, which could add quite a bit to the cost.

[...]

2 - Cost.

It is dead easy to end up paying 70p-£1 each for these, as prices are highly variable. Mine have usually cost more than the wood in toto, but I am probably being cautious on the number used.

[..]

3 - If using these for mounting a wallplate I also get some large washers to prevent it sinking into the wood - say 2-3 times the screw diameter.

[...]

 

Today's challenge (should I wish to accept it) is to get to the bottom of all of these issues. (This post will not self-destruct in 5 seconds.)

 

It's an ill wind that blows nobody any good - remember? Now that I have extracted more than a hundred single meters of M12 threaded bar with nuts and end-plates (washers) from the grip of the concrete, they are lying on my stillage. Waiting for a project. Well, here it is.

 

Just got to make a couple of phone calls.

 

 

 

[ToughButterCup]

19 hours ago, MikeSharp01 said:

Just run the stuff you have past the SE and all will be well.

 

Ave! Oh Sage of the South: all Hail !

One Land One King! 

You did speak, I did ask,

From the cloud, the Sage of Structures did answer

And, lo!  All was well !

 

Just off to polish me threaded bar. I have a job for it. 

[ToughButterCup]

Right, got the go-ahead for the threaded bar: now which resin should we use in which to embed the bar.

Durisol say 2 Part epoxy resin for High Loads, and 'ask the architect'

 

Yeah, but what do you say?

[Ferdinand]

2 minutes ago, recoveringacademic said:

Yeah, but what do you say?

 

Get it in writing.

 

And keep you eyes open for sales on 1m long masonry drills :-).

Edited September 22, 2017 by Ferdinand

[MikeSharp01]

Great news on the threaded bar front. I was thinking as I drove down (across - as believe it or not our new house is due East of our current one, doesn't seem right somehow) this morning about two things:

 

1. That these steel threaded bars will be good cold bridges and that you might find just treating the ends with a PU cap to deal with it.

2. That you need to ensure that you mark out the joist positions on the wall plate before you drill the wall, or otherwise control the fixing positions, so that you don't end up with a nut, washer and short length of threaded bar sticking out just where you want a joist.