levelling joists for decking

[Jupiter01]

Thanks again @Seb101.

 

[Jupiter01]

Can I use these for screwing the joists together:
https://www.toolstation.com/shop/p86579

I will use green decking screws for the decking boards

 

[Seb101]

What's the largest difference in level between one corner of the deck to the other? Are we talking millimeters or 10s of centimeters? If you want to to keep the deck as low as possible to the ground, there is no reason not to just use plastic spacers. There are spacers between my bricks and the deck joist in several places where I didn't get the brick height perfect. When using spacers your biggest concern is making sure the deck doesn't wobble off the spacer stacks, but you can get around that by anchoring it to the concrete base in each corner with a concrete anchor.

 

[Jupiter01]

I think my gap is too big. It's an inch at the highest point.

 

[Seb101]

I think my gap is too big. It's an inch at the highest point.

I don't think that is too much. I have a pack of Broadfix shims that I use for jobs like this and it would only be a couple of the thicker ones. https://www.screwfix.com/p/broadfix-assorted-plastic-shims-medium-200-pcs/80408

Just level it up at each corner, anchor to the concrete through the shim so the shim can't slip out. Then go along and wedge shims in between the joist and concrete at 60cm gaps so the weight is evenly supported by all the shims.

 

[Jupiter01]

That's great. I can use them too!
Are these screws ok for the joists?
https://www.toolstation.com/shop/p86579

 

[Seb101]

That's great. I can use them too!
Are these screws ok for the joists?
https://www.toolstation.com/shop/p86579

Cool. I assume this is just a normal occasional use deck? Those shims aren't strictly designed to be load bearing, but they will be fine if they are spread around evenly at 60 cm intervals.

The screws are fine.

 

[Jupiter01]

Thanks for all your help @Seb101. I really appreciate it

 

[Jupiter01]

Hi Guys,

A follow on question please. Do I need noggins in this joist frame (4.2m x 2.20) and how should they be positioned? staggered, how many per joist set, etc.

 

[Seb101]

Hi Guys,

A follow on question please. Do I need noggins in this joist frame (4.2m x 2.20) and how should they be positioned? staggered, how many per joist set, etc.

Assuming you are laying the boards perpendicular to the joists (so left to right in your picture) then there is no need for noggins, the deck boards will secure the whole thing together.

 

[Jupiter01]

That is how I am laying it but seen quite a few videos where they are fitting noggins. Thought I'd check with the experts.
Is there any justification for noggins because I am using 3x2 joists and it may reduce bounce, etc.?

 

[Seb101]

That is how I am laying it but seen quite a few videos where they are fitting noggins. Thought I'd check with the experts.
Is there any justification for noggins because I am using 3x2 joists and it may reduce bounce, etc.?

It might reduce a small amount of bounce on the boards that exactly align with the noggins. I guess the complete answer is that you don't need to install them, but if you have the time and the timber spare, there is no harm in over-engineering it

 

[Jupiter01]

Thanks again @Seb101. I had to make an executive decision yesterday and decided to go without these. Instead, I've opted to put "legs" on more regular intervals. Every 60cm.

Here are a couple of pictures of my working progress...