Deck Construction

[adam.baxter]

Guys,

I have a question, I am in the process of building a 6x6 Deck in Brisbane.

I cut, welded and got the posts hot dipped. I am supporting the bearers on form working frames. What I have noticed is that none of the timbers are exactly what I ordered. i.e. ordered 250x75 bearers but they are more between 240-245x75. How does one go about making this level? I can either make the tops of all the posts at the same height and plane off the tops of the bearers to suit afterwards or have the posts at slightly different heights to make up for the uneven heights of the bearers. Also the joists are not perfect, I assume this is normal for rough sawn.

Regards,

Adam Baxter

[r3nov8or]

I would set the posts at the same level and check out and/or pack the under side of the bearers over each post to level the tops. Do the same with the joists where they meet the bearers, Then using a straight edge across the joist surface you may find some need some planing in places.

[barney118]

It doesnt look like you have the footing pads down? Are you planning on building the deck then setting the pad heights, then adjust the base of the concrete.

[adam.baxter]

Going to hang the posts from the bearers then fill holes with concrete.

[ringtail]

r3nov8or is on it. Keep the tops of everything at the same height. Easy way to check for flatness is to use string lines and a gauge block. Cut 3 blocks of timber out of a pine stud. Put 1 under each end of the stringline (which runs across the joists) and use the third as a gauge to where you need to plane or pack. You will probably find the shrinkage is worse on the ends of the timber as the moisture leaves the endgrain. Needless to say, seal the ends of bearers and joists with bitumen or similiar ASAP, and all checkouts of course

[stevoh741]

while your at it with the bitumen paint, hit the bottom of the gal posts before they are encased in concrete. Ideal would have been to use hold down bolts which you can therefore adjust the height of the posts (within reason) to suit the bearers. Your way is fine to just a bit more work IMO. Keep the pics coming, love a good deck build.

[intertd6]

Guys,

I have a question, I am in the process of building a 6x6 Deck in Brisbane.

I cut, welded and got the posts hot dipped. I am supporting the bearers on form working frames. What I have noticed is that none of the timbers are exactly what I ordered. i.e. ordered 250x75 bearers but they are more between 240-245x75. How does one go about making this level? I can either make the tops of all the posts at the same height and plane off the tops of the bearers to suit afterwards or have the posts at slightly different heights to make up for the uneven heights of the bearers. Also the joists are not perfect, I assume this is normal for rough sawn.

Regards,

Adam Baxter
The timber should be 0mm to + 3mm tolerance, anything under is not adequate for the design, you could just hang the posts off the bearers , put on the joists & decking , then level the whole show off the top surface with the screw jacks on the formwork frames, concreting under the column base plates casting in HD bolts whatever the height. Turn the frames diagonally so they are centrally loaded & wont try to tip over
regards inter

[ringtail]

But you will get 5% shrinkage out of F14 easy. So a 240 will loose 12 mm quite easily. Ive lost upto 15 mm on my 200 x 75's

[intertd6]

RT thats true for green to seasoned & probably a bit more for the blackbutt that is shown there, the tolerances I quoted are for green timber off the saw, if it was seasoned then that changes things entirely.
regards inter

[barney118]

I would say you would need some bracing for a deck that height on those skinny poles. What are your future plans for the house? The reason I ask is it may have payed off now by piering down for the posts and laying a slab down under in one go.

[ringtail]

RT thats true for green to seasoned & probably a bit more for the blackbutt that is shown there, the tolerances I quoted are for green timber off the saw, if it was seasoned then that changes things entirely.
regards inter


Agree. Another reason why LVL's are becoming popular for deck construction. Not sure if thats blackbutt though, we get bugger all of that up here. Its pretty popular around the mid NSW coast.

[intertd6]

Quite a few mills that I know of around nthrn NSW send nearly all of their larger sectional sized timber to QLD, especially blackbutt because we have a good supply of large logs & just looking at it, the yellowing, the nice gum vein with that red stain points in the direction of blackbutt. I dont know what level of H rating LVL's achieve & at what cost, but undoubtedly thats what will be used in the future when more sustainable forests are locked up for the greens.

regards inter

[ringtail]

I must admit, Ive never received blackbutt as framing ( for decks), its always been spotty, ironbark or forrest reds. I have got KD blackbutt for doing stairs and servery tops etc... without too much trouble. With the LVL's, H2 or H3 and 10 - 15% cheaper than F14 for the last deck I built using them and getting cheaper than hardwood all the time. I used them for everything ( as was the spec)- bearers, joists, roof beams and rafters. Very happy with the result - long, perfect, stable lengths.

[adam.baxter]

Thanks for the replies guys, all the underfloor timber is F17, roof is using 21c bearers and LVL rafters. There is cross bracing for the posts that will be installed once the concrete has set. I know the frames are a bit unstable but I nailed 1 joist to half of the bearer closest to the house and it has given it a lot of stability.

I am still at odds whether to get the top of the joists level with no packing or planing then hang the posts wherever they need to be. OR... set the tops of the posts to all the same level and then pack or plane the joists to suit.

Is linseed oil a suitable replacement for bitumen on the check outs?

[ringtail]

The linseed oil will promote fungus and mould. 4 lt tin of ormanoid bitumen is about $50 - well worth it, leave in the sun to make it more brushable and/or thin with a little bit of turps

[adam.baxter]

Bit of progress on the weekend. Ledger has been fully bolted to the house at 600 centers

Made up a measuring jig for the first bearer to make it the correct distance from the house, using a plumb bob to centre it.

Few questions I do have is around the joists, stair landing and handrail posts. The width for the stair landing is 1015 as you can see from the plan below. This is all new to be so please forgive any mistakes or misunderstanding.

1. I need know the correct way to attach the handrail posts to the joists. I assume notch the bottom of the post to the Inside of the outer most joist leaving atleast 1/3 of its original width and use 2x M10 or M12 bolts to hold it. I am letting the decking hand 30mm over the edge of the Joist.

2. Should I make the outer edge of the handrail post finish with the end of the decking? or extend the deck a few cm beyond the posts... might need a small bit of timber attached to the outer side of the joist?


89002

890018900088999

[ringtail]

You got it.

1. Check out the post to the same depth as the joist and use 2 x M12 bolts counter sunk into the outer face of the joist.
2. Yes keep the outside of the post flush with the outside of the joist and cut the decking to go around the post - can be fiddly. 30 mm over is good for over hang. Sometimes I will run a fascia around the whole deck to protect the joist better and give a good surface to paint, in which case you have to allow for it with the decking so it projects another 30 mm over the facsia. If you use a fascia do not nail the decking to it as the joists and fascia will move differently. If you dont use a fascia there is still no need for any additional timber until you get over 80 - 100 mm overhang but 30 - 50 is a good amount

[barney118]

I would appreciate some thoughts on ledger board to a brick veneer house, would it be allowed to take such load? Why did you choose hardwood given it would be open to the elements?

[adam.baxter]

The ledger is attached to the main house timber bearers. 30cm long bolts go through the ledger, brick, lintel, packers, bearer. The brick can take downward load but not in and out.

What is the alternative to hardwood?

[barney118]

The ledger is attached to the main house timber bearers. 30cm long bolts go through the ledger, brick, lintel, packers, bearer. The brick can take downward load but not in and out.



I assume you mean studs.




What is the alternative to hardwood?

Treated pine.

[adam.baxter]

No. The ledger bolts through the brick into the Bearer that holds my house up.

I'm not convinced that treated pine will last in exposed areas

[adam.baxter]

Little update. Going to concrete the first 3 posts in this weekend.

Yes I will drain/clean the holes out before pouring concrete ;)

[ringtail]

Meant to rain tomorrow - bugger

[stevoh741]

I'd be painting the parts of the post that will be in contact with the concrete with bitumen before you pour.

[ringtail]

Tru dat. (Flaccid Member Steve, WTF)

[stevoh741]

Tru dat. (Flaccid Member Steve, WTF)

Its the one just before golden member. Was wondering how long till someone noticed :D

[adam.baxter]

is bitumen paint necessary on hot dipped posts?

[ringtail]

is bitumen paint necessary on hot dipped posts?


Always a good idea regardless. I reckon you'll be right with the weather - they seem to change the outlook every 5 mins.

[stevoh741]

apparently the concrete can degrade the gal. Some science stuff was posted here a while ago thats prob debatable but I was always taught this similar to using damp course under steel frame. For the small amount of effort it takes then worth doing IMO.

[r3nov8or]

Maybe I missed it, but I haven't seen this recommendation when using HDG stirrups?

[barney118]

apparently the concrete can degrade the gal. Some science stuff was posted here a while ago thats prob debatable but I was always taught this similar to using damp course under steel frame. For the small amount of effort it takes then worth doing IMO.

Search on google and there seems to be no problem with gal. There is an issue with zinc/al or zincalume though the aluminum reacting.

[ringtail]

Maybe I missed it, but I haven't seen this recommendation when using HDG stirrups?

Thats a very good point, me either

[intertd6]

coating hot dipped steel with bitumen coatings I believe is a requirement of the masonry code for embeded steel items + 100m of the sea but not in a splash zone of salt water (stainless steel for that).
regards inter

[stevoh741]

When I get some time I'll have a search for that old thread

[strangerep]

With the LVL's, H2 or H3 and 10 - 15% cheaper than F14 for the last deck I built using them and getting cheaper than hardwood all the time. I used them for everything ( as was the spec)- bearers, joists, roof beams and rafters. Very happy with the result - long, perfect, stable lengths.

LVLs for exterior use, like for a deck?? (I was under the impression that even H3 LVLs are not suited to long-term exposure to wetness.)

[strangerep]

[flaccid member is] the one just before golden member. Was wondering how long till someone noticed:D
I noticed ages ago, but it's way too sad when it actually happens. :C

BTW, to become a golden member, do you have to go through a formal hot-dipping ceremony?

[stevoh741]

I noticed ages ago, but it's way too sad when it actually happens. :C

BTW, to become a golden member, do you have to go through a formal hot-dipping ceremony?
Lol

[ringtail]

LVLs for exterior use, like for a deck?? (I was under the impression that even H3 LVLs are not suited to long-term exposure to wetness.)

They need some lovin before install - paint all round

[stevoh741]

They need some lovin before install - paint all round

And joist protection like Malthoid etc. I'm with u ringtail, been recently using LVL and it is so nice not to have to wrestle the @@@@ out of every bit of hardwood to try get it straight. That said I still like my hardwood and still use it if I can buy it straight. Lvl lighter on back and wallet which is also a nice plus...

[strangerep]

[LVLs] need some lovin before install - paint all round
Hmmm. What paint do you use, and how many coats?
And how long have you been using LVLs outside in this way?

[ringtail]

Hmmm. What paint do you use, and how many coats?
And how long have you been using LVLs outside in this way?

The last deck I built I used bitumen all round which was a messy PITA. Good oil based primer is fine, but the bitumen is much better. I thinned the bitumen for the first coat and then put a top coat on with no thinning. The oldest deck Ive done using them is coming upto 3 years old ( and went totally underwater in the floods) but they have been used for a lot longer than that. I would think twice about using them on a totally uncovered deck but anything with a roof is fine, including using them for all the roof framing. You can also seal them up with decking finish like aquadeck or sikkens no problems. Hyne used to have a "recommended paint system" for them but its just common sense. Protecting the top is the only real "must do".

[strangerep]

I would think twice about using [LVLs] on a totally uncovered deck
Ah, now that's a bit closer to the good oil.


but anything with a roof is fine, including using them for all the roof framing. You can also seal them up with decking finish like aquadeck or sikkens no problems.
Except that the sealing properties of that stuff don't last anywhere near 10-20 years that we'd like it to.


Protecting the top is the only real "must do".
And the ends, I presume?

[ringtail]

Ah, now that's a bit closer to the good oil.

Again, its fit for purpose - would I used pine for a uncovered deck, chit no


Except that the sealing properties of that stuff don't last anywhere near 10-20 years that we'd like it to.


True, but as its not exposed to light like decking it would last a bloody long time


And the ends, I presume? - Goes without saying

[adam.baxter]

I have concreted some of the posts in but they are not exactly inline. is this a problem?

[ringtail]

I have concreted some of the posts in but they are not exactly inline. is this a problem?

Makes things more difficult, how far out are they ?

[adam.baxter]

1-2cm at the most.

problem lays in the way i chose to support the bearers... they are not perfectly straight so when i bolted the posts up to them and hung them in the hole it was out of alignment a bit.

I dont think I will use this technique again, unless i have LVL's as bearers

[ringtail]

1-2cm at the most.

problem lays in the way i chose to support the bearers... they are not perfectly straight so when i bolted the posts up to them and hung them in the hole it was out of alignment a bit.

I dont think I will use this technique again, unless i have LVL's as bearers

Always a problem. Some guys like doing it that way, I dont like it personally. Profiles and string lines for me, posts in first and build up from there.

[intertd6]

1-2cm at the most.

problem lays in the way i chose to support the bearers... they are not perfectly straight so when i bolted the posts up to them and hung them in the hole it was out of alignment a bit.

I dont think I will use this technique again, unless i have LVL's as bearers
There was no problem with your construction technique, you just needed to use a string line at critical points along the process.
regards inter

[Bloss]

:whs: I reckon for DIY that's a better way - all can have their problems - most can be fixed after nowadays.

[adam.baxter]

some more work... working on the stair landing now. going to pickup some hot dip stringers this week. 13 steps