Installing new floor joists for moving bathroom to 1st Floor

[Dacia64UK]

Hello,
I'm currently looking at a project where I wish to re-locate the bathroom to the first floor.
In order to gain some height in the room I want to move it I am looking at removing the existing floor joists and installing new ones.
I have researched on the NHBC website and have decided to use C24 75*147mm timber for the joists.
It also stated about embedding them 100mm into existing masonry, however reading online it maybe easier and more accurate to line the joists up using a Ledger/Wall plate using same dimension joist timber.

What I cannot seem to find are
°What recommended size threaded rod to use and spacing.
°Best Epoxy Resin to hold threaded rods into masonry.
°Recommended Depth of rods into masonry.

Many thanks in advance

[Job and Knock]

°What recommended size threaded rod to use and spacing.

In my experience most anchors we've used were M12, M14 or M16. As all of these sizes of rods are capable of supporting many tons each I doubt that the actual diameter makes much difference in your case (i.e. low loading, domestic). On commercial stuff we often space at 400 to 600mm, depending on the substrate.

°Best Epoxy Resin to hold threaded rods into masonry

I doubt that there is a single best option here. I've used resin systems from Fischer, Ancon, Hilti, Spit, Bison, etc and both injected and capsule systems. I can't say that any one is better than the other. Hilti, are, however, a lot more expensive than the rest. Personally, I prefer two pack resins with a mixer nozzle, such as the Fischer systems. To use these effectively you'll need to ensure that you blow-out the hole after drilling with what one colleague referred to as a "Swedish enlargement pump..." (not sure what he meant by that ) - or a blow-out pump.

Blow Out Pump 001_01.jpg (29.26 KiB) Viewed 2631 times

because loose materials left in the hole will reduce the effectiveness of the anchor

Ideally you'll also need to buy a special applicator gun to handle the resin (generally £20 to £35 - some resins are gun specific, so check) as the tubes are larger diameter than a standard tube of silicone. There are some systems out there which use "standard" caulking guns, but because the resins are so heavy (viscous) they can really only be used with heavy-duty caulking guns (such as those by Cox, Tajima, Ox, etc) - and even they are not as easy to use as the specialist guns. Using resins with lightweight "skeleton" guns just breaks the guns in next to no time, if they work at all.

Finally you really do need to ensure that you have a couple of extra mixer nozzles available before you start. The 2-pack resins go off quickly, so even breaking off for 15 minutes in the middle of a tube to answer the phone or have a coffee will see the nozzle rendered useless (the material sets inside the nozzle).

°Recommended Depth of rods into masonry.

That depends on the masonry, really. My experiences have all been with solid masonry or massive (dense) concrete - for blockwork or single skin brick we generally use different (non-resin) systems. You'd be well advised to look at the individual suppliers web sites for technical details on this. I'd recommend taking a look at the Fischer web site as a starting point and maybe talking to their technical hotline. the reason for a bias towards Fischer is that their stuff works and is available more generally than, say, Hilti or Spit products (which tend to be from specialist trade outlets only)

[Dacia64UK]

Fantastic !

Cheers, had a look at the RawlPlug stainless steel threaded rods and epoxy, emailed their technical support twice to confirm the details and specs of their products.....no reply...same happened with StrongTie.

Will have a look around the Fischer site

[Grendel]

I've just used this stuff from screwfix ,
https://www.screwfix.com/p/easyfix-kem- ... 80ml/1457j
Seemed decent enough , reasonably priced and comes with two nozzles. For the metal work I used 16mm stainless allthread and I tend to try and get the lengths as long as possible. For spacings if you are doing a floor and using a ledger stick one in between each joist. More is better than less and on poor brick or stonework we have sometimes put in two between each joist position.

[Dacia64UK]

Thanks for the reply's, I had a reply from Fischer specifying the Resin as being :

https://www.toolstation.com/shop/p56829

but didn't get a specific reply regarding which threaded rod as yet, but looking also on toolstation as Fischer recommended I found these :

https://www.toolstation.com/shop/p33516

M16 x 190mm

...so if I embed them 90mm into the wall (one wall is 130mm deep and the other 220mm) that will leave 75mm for the Ledger Timber and 25mm left for the nut to attach to ?

[ayjay]

I have researched on the NHBC website and have decided to use C24 75*147mm timber for the joists.

If that size is the right spec for the span (with no spare capacity for the bath weight) then the joists taking the direct weight of the bath should be doubled up.

[Dacia64UK]

The span is 3m, and I've went for spacing of 400mm which gives a span of 3.29 ? (Highlighted in Orange)

With joist noggins staggered at 600mm centres

Span.jpg (310.86 KiB) Viewed 2557 times