Joists....Have I boobed?

[joe90]

On 01/12/2023 at 16:52, joe90 said:

solution., 1/2” ply, glued and screwed both sides of the joist.

 

[Dee]

Oh, it is glued too! Forgot to mention that

1 hour ago, MikeSharp01 said:

Glue (probably a PU would be enough

 

[saveasteading]

2 hours ago, Dee said:

16 screws all over the place!

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

[saveasteading]

2 hours ago, Dee said:

16 screws all over the place!

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

[saveasteading]

2 hours ago, Dee said:

16 screws all over the place!

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

[saveasteading]

2 hours ago, Dee said:

16 screws all over the place!

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

 

[saveasteading]

Sorry folks. It didn't seem to submit so I tried again and again. any way I can delete these?

[Dee]

7 hours ago, saveasteading said:

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

 

Sorry, I don't understand?

I had nothing to fix to below the bottom of the joist? Please expand what I should have done? Appreciate the advice 

[saveasteading]

I mean that the notch is what needs to be spliced, so put some screws in the lower area of the ply splices.

When load  is applied to the joist, the bottom goes into tension. The ply can take that tension at the bottom , holding it stiff across the gap. It will do that most efficiently if there are fixings lower down ( unless there are and I'm not noticing them).

[Dee]

So, giving the bathroom ...and you guys, a rest while I figure out the heating system which seems to have developed a mind if it's own!

I have 18 rads, of which 6 decided not to heat up atall.

So I turned off fully the 12 hot rads, and all 6 cold rads heated up .

One by one I turned the 12 back on and after a few days all rads were still lovely and hot....until 2 gradually went cold and despite my best efforts have remained so.

I have tweeked and twiddle the LS valves on those pipes that I believe to be effecting the 2 duds but no improvement.  All rads bled, recently drained system when boiler was replaced...totally foxed!

 

[joe90]

It all needs balancing, from cold the ones that heat up first should be restricted to allow the others to catch up, this is done on the valve on the other end of the radiator to the TRV.

[Dee]

Yeh, I have properly balanced the whole system a few years ago, down to using a multimeter to get the temp to 12⁰ across the pipes....took 2 days. I was hoping for a quick fix this time!

What I don't understand is that on all the hot rads the LS is literally barely open, not even 1/4 turn, even those the farthest away from the boiler.

[TonyT]

On 10/12/2023 at 10:52, saveasteading said:

Not quite all. the notch is out of the bottom, and that is the bit of ply that needs to be fixed hard. a few more screws down there, if you can.

What’s screws would you use?

interested as I thought you should only use nails to prevent shear?

 

[saveasteading]

2 hours ago, TonyT said:

should only use nails to prevent shear?

Haven't heard that theory. No, screws do resist shear. 

I've taken to only buying branded screws, meaning not own-brand.

[joe90]

Nails perform at their best when resisting shear force (force pulling sideways) while screws are designed to resist withdrawal force (force pulling outwards).

 

I have heard that but what you have done is fine in my opinion along with glue.

[saveasteading]

Ahem. An interesting statement.  Yes screws perform well in pullout, but they all have shear resistance based on how much shank is there. 

But nails hold things together too, and are not easy to pull out.

A good interview question....when would you choose a nail or a screw?

I prefer screws because I'm rubbish with a hammer, and there is a second chance.

 

In this case the advantage of screws is in ease of fixing.

[joe90]

I remember a thread here a long time ago where someone used screws in joist hangers and was told it should have been nails because they work best in shear 🤷‍♂️. I guess it depends on the type of metal and diameter.

[markc]

Connector screws are made for joist hangers etc. short shank under head designed for shear loads 

[saveasteading]

7 minutes ago, joe90 said:

I remember a thread here

indeed, you've hit the nail on the head there.

 

I think the likelihood is that a pro would rather bash nails in than screw, so the nail spec has been assessed.

 

[joe90]

https://www.yourownarchitect.com/can-screws-be-used-with-joist-hangers/
 

Fir some reason i can’t cut and paste the relevant paragraph about using hanger screws or nails.

[saveasteading]

10 minutes ago, markc said:

short shank under head designed for shear loads 

i had never thought of that purpose for the plain shank. i feel educated.

[joe90]

Screws for joist hangers have a different shank to fill the hole in the metal (every day is a school day .)

 

Edited December 28, 2023 by joe90

[SteamyTea]

10 hours ago, joe90 said:

Screws for joist hangers have a different shank to fill the hole in the metal

That makes them bolts.

[joe90]

2 hours ago, SteamyTea said:

That makes them bolts.

No,  A bolt is a non-tapered fastener that uses a washer and nut to hold objects together. A screw is a tapered fastener that mates with an existing thread or creates its own thread in a material as it turns.

[dpmiller]

5 hours ago, joe90 said:

No,  A bolt is a non-tapered fastener that uses a washer and nut to hold objects together. A screw is a tapered fastener that mates with an existing thread or creates its own thread in a material as it turns.

 

so what's a set- screw then?