Raised deck assistance

[jackeeeyyy]

Good evening,


I am looking to start my own deck project but after watching a lot of YouTube videos and reading a number of tutorials I am questioning my own design (rough Sketch on Publisher and not drawn to any sort of scale!)


I am seeking on advise as to whether I am over/under engineering my deck which will be raised by approx. 300mm


Here’s the breakdown.

- 600mm deep holes for the 100x100 fence posts which will sit on split breeze blocks, post creted in.

- Joists attached to the fence posts with coach bolts and washers driving through both joists where necessary.

- Joists attached to the outer “joists” with coach screws (where they cant be attached to a post) at 400mm apart.


So I guess my following questions are;


- Is this fit for purpose as a base?

- Do these joists which aren’t supported by posts need hangers?

- Do I need noggings?

- Or is it terrible, bin the idea and hire a professional?


Appreciate any assistance.


Thanks,

 

[Mr diy a lot.]

There is a million ways to build a deck and this looks like a solid design to me. She is going nowhere.

600 deep holes for posts might be overkill on the excavations given you are only raising 300mm but if you enjoy digging holes go for it. 400-500 fine too.

yeh def need noggins down the middle will keep all your joists from twisting in the middle.

no need for hangers unless you are planning on letting your pet elephant jump up and down on your deck.

Worth spending extra cash on composite deck boards in my opinion unless you want to treat it every spring.

No need for a ‘professional’ - you can do it!

 

[big-all]

just make sure you keep below 300mm at the highest ground level to avoid the need for planning
also the 50% rule iff a small garden

 

[jackeeeyyy]

Thanks both for your replies, I really appreciate it.

I was planning on using 3m posts on each corner to build a pergola from. the rest would be 1.5m (if that)
So could I get away with doing the 4 corners (for the pergola) at 600mm then 400 for the rest of the posts?

Thanks

 

[Mr diy a lot.]

yes should be fine.

 

[Jowwy]

Thanks both for your replies, I really appreciate it.

I was planning on using 3m posts on each corner to build a pergola from. the rest would be 1.5m (if that)
So could I get away with doing the 4 corners (for the pergola) at 600mm then 400 for the rest of the posts?

Thanks

Have you thought about building the pergola ontop of the deck, rather than incorporating within the deck structure, just in case you may want to take it down in the future???

 

[jackeeeyyy]

I've done a 300mm hole with a split breeze block leaving 200mm for concrete. Is that enough for the inner posts?

 

[John D v2.0]

I've done a 300mm hole with a split breeze block leaving 200mm for concrete. Is that enough for the inner posts?

Main thing is you should have got down to the subsoil and it should be solid and square, and 150mm of concrete in the bottom to build off

 

[morqthana]

Worth spending extra cash on composite deck boards in my opinion unless you want to treat it every spring.

Or hardwood.

But if you use those grooved boards, make sure you install them grooves down.

 

[jackeeeyyy]

Or hardwood.

But if you use those grooved boards, make sure you install them grooves down.

What's the bonus with hardwood/composite Vs normal deck boards?

 

[morqthana]

The first 2 don't rot - (or at least hardwood won't for a very long time). Composite has problems with scratches and wear paths which can't be removed, and (used to at any rate) suffer from UV fade. Normal deck boards are a constant maintenance chore to maintain some degree of weatherproofing. Remember that pressure-treating does not make the wood water repellent - you still need to treat it.

 

[StephenOak]

The first 2 don't rot - (or at least hardwood won't for a very long time

I don't think it is quite that simple. Some hardwoods are more resistant to rot that other woods, e.g. chestnut which was used for paling. But the hard / soft divide is about how they reproduce and not the nature of the wood. Hence balsa is a hardwood and yew is a softwood.

 

[morqthana]

That's true - I was being a bit generic.

So - green oak it is, then.

jackeeeyyy - seriously - hardwood is not without its cost issues, and I've no idea how long you plan to stay where you are - it might be pointless to shell out for a hardwood deck with a virtually maintenance free life of many decades.

If you do, FGS don't oil it or whatever, as you'll then have to do it every year - just leave it to go the colour it wants to.

And if you want softwood, reclaimed scaffold boards can look pretty good - do an image search for reclaimed scaffold decking.

Yes, you'll have to treat them every year or two, but at 1½" thick you don't need such a substantial base. I believe the technique is to lay the boards, then hire a floor sander and give them a good going over, then apply your decking oil/water-proofer/whatever.

 

[JohnD]

But if you use those grooved boards, make sure you install them grooves down.

What makes you think that?

 

[morqthana]

Its the right way. Grooves down provides ventilation where the boards rest on the joists. Grooves up provides traps for water and dirt to lie there promoting the growth of algae etc and actually make it slippier than a smooth surface.