Decking building - advice

Hi
I've been researching deck building so that this time I actually follow some instructions / guidance on how to do it properly (last time was very successful, but some of the niceties weren't perfect - e.g visible joist hangars, posts slightly off vertical etc). And this time it will be double the length and width, so a larger project in any event.
Just for some background, the position is this:- - 4.8m x 4.5m deck - starting next to the house (a good few inches away), footings will stand in bolt down post holders on paving flags (not going for ledger board option to avoid risk of compromising dpc) - ground slopes away slightly (down by about 300mm max)
My first question which most decking advice leaflets don't seem to cover is locating the newel posts for the handrails. From pictures there seem to be two options. Firstly locate the posts on the inside of the frame. This seems messy to me as notching the deck boards around the posts (particularly in the corners) could give some really ugly finishes. Second option is to locate the posts on the outside of the frame. Sounds perfectly straight forward, apart from the fact that I can't work out how you'd do this at the corners, as to be on the outside of the corner for both edges means floating in mid- air.....
Next, a simple question - joists. Some advise using hangers, some advise three 125mm screws. Which would you use?
Next, supporting posts. TMHM (?TMH?) previously disuaded me from putting in effectively 16 posts (4 onto the paving, the other 12 concreted into the ground) to support the overall structure, and instead just concrete the posts at the corners and then use some form of padstone on a level base to support the other posts. Two questions arise here: - would there be a membrane between the foot of the post and the padstone to stop water transfer, or would conversely you recommend no membrane so that the post doesn't stand in a pool of water. - second question is how many to put in? Would you just put in posts around the side of the frame (four corners, then two on each side) or would you add an additional four underneath the main body of the deck?
Finally, what order would you do things in? I'm conscious that getting the posts in the right place is going to be essential. My thoughts are to build up the "square" frame, and use that to locate the precise location of the posts. Then put in the posts, secure the frame to the posts and then add additional supporting posts. Then the joists and noggins. Next, newel posts and steps up, and finally deck boards.
Advice, as ever, gratefully received. And for those who are experts about this, a guide which is more detailed than most already on the internet would be a great addition to the diy wiki.
Matt
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 21 Jul, 10:01, snipped-for-privacy@gmail.com wrote:

Thinking about this some more, the notching shouldn't be too difficult should it? I just need to locate the post holes away from the very corners so that the newel posts can be bolted directly into the corner. Then I just need to space the deck boards appropriately.

I think I'll go down the screw route here as then there aren't issues with the deck boards sitting flush onto the frame (which was less straightforward last time when I used hangers)

Ignore the membrane question - the pool of water argument won it for me....

Again, thanks if anyone can help provide additional steers (or links to good thorough guides on the internet which I've singularly failed to find).
Matt
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com wrote:

Space the ledger 10mm away from the wall, never had a problem.

Also makes it hard to fit the balustrades.

Tricky. You can use two posts, actually looks good. Failing that what I do is cut two half laps, leaving just a quarter of the post, then glue & screw to strenghten it.

Depends on if you can get screws in from the back of the joist. I use 6 x 90 turbogold coach screws http://www.screwfix.com/prods/46700/Bolts/Turbo-Coach-Screws/Turbo-Coach-Screws-Zinc-Yellow-Passivated-M6-x-90mm-Pack-of-100 which are fantastic for frane construction. 14.4v driver will put them in, no pilot hole, impact driver whacks them home in under 4 seconds. Easier to pull a sailor off your sister than break a joint made with two of these.
I only use joist hangers if I cant use the turbogolds.

I use a membrane primarily to stop damp from the ground wicking up. End grain sealer prevents any water damage.

Depends on the size of the joists. A 150 x 50 will span 3 metres without a central support, if your deck is 4.5/4.8 you will need extra support. Bear in mind that if you bolt in noggins, then a post attached to it will support two joists.

Exactly what I do. Spot on.
Don't have time to write one, too busy doing quotes for decks :-)
Happy to help anytime on/off group.
--
Dave - The Medway Handyman
www.medwaydecking.co.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.