Thread: Reality Check
9th April 2009, 09:06 PM #1
Okay I wanna build a 12x6 timber framed shed (eventually.)
What kind of sizes and amount of timber would be needed for the frame?
How hard will it be / how much will it cost to get an engineer to approve the design?
I can get hardwood (eucalypts) from work for decent prices, or cypress from in town for (most likely) alot more. Termites aren't rampant around here but they do exist.
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9th April 2009, 09:43 PM #2
Are you talking about building a 6X12 metre shed? That's pretty big.
Are you building on a slab?
You need to draw up a basic design, then you can take that to a drafting consultant to work it into plans suitable for council. The consultant should also be able to organise any engineering approvals.
The hassle and the expense of all of this is why we tend to buy pre-fab steel sheds like Titan and so on. When they supply a shed they also give you all of the plans and specs you need for council approval. You are more than capable of erecting a prefab metal shed.
By the way. Those quiet and invisible termites in your area will become rampant whenever you provide food for them. Place a lump of dry timber in your back yard and watch it disappear.
9th April 2009, 09:57 PM #3
Hi last weeks KFC,
You shouldn't need an engineer if ur in Qld but I believe u will need plans drawn by a Building Designer if the structure is higher than 2.4m & more than 10m2. (u talking metres or feet?) should be someone on here that can sort u out with plans when u need them, if not PM me & eye'l help get ewe sorted.
9th April 2009, 09:59 PM #4
Theres various types of timber framed sheds.
Stud walls like a house.
Pole frame (often metal clad)
My shed will be about 12.6 x 6 when I get round to it.
Been distracted by a few unavoidable things.
Weatherboards over stud walls, coupled rafters with collar ties and NO trusses
all designed from timber span tables so I won't need to use nor pay for an engineer.
Wall plates 90 x 45 pine
Studs 90 x 35 at 600mm centres
Rafters 200x50 F7 oregon (I've already scrounged them)
Roof/ceiling battens 70 x 45 or 90 x 45.
I'll use concrete stumps, not a slab foundation. I'll put a concrete floor in after the stumps are in. After the sheds built I'll drop a floating floor over the slab.
I'm considering treated pine for wall framing
Narrow windows under the eaves all around to let light in but not the direct sun.
Very inclined to fit ceilings/sarking & insulation.
ps you're welcome to a copy of my plans (though they are not finished yet ).
9th April 2009, 11:14 PM #5
There u go, you can use someone elses plans then get your own site plan drawn.
10th April 2009, 09:56 AM #6Skwair2rownd
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Some good info and offers of help here my feathered friend.
The idea of building on concrete stumps and putting the slab in later (Echidna) will help to spread your spending spree out of a longer time.
We are all awaiting the call to a working bee and, therefore, your mother's fine cooking.
10th April 2009, 10:11 AM #7
While treated pine is appealing to me the wombat saw mill has opened other timber opportunities and the wall frames might end up being made from home sawn macrocarpra. I've got a few logs in the backyard and access to many more logs if I want them.
I used to have a timber grading lisence many years ago but the system changed so it's gone. But as I recall ungraded timber is regarded as F4 so I'll just use F4 span tables.
I have designed to class 1 standard not to outbuilding standards just to ensure a little flexibility if I ever need to convert it from a shed to another use.
10th April 2009, 10:25 AM #8
As Artme noted putting a slab in later gives you an immediate workshop.
10th April 2009, 09:17 PM #9
Can I borrow those plans
What's the argument about rafters vs trusses?
10th April 2009, 11:18 PM #10
Rafters come out of span tables whereas trusses have to be designed by a qualified engineer.
But you could do coupled rafters as a truss like assembly.
I'll try and whack a pdf on here.
Note the collar ties need to be 1/3rd of total roof height above the top plate.
The drawing in the pdf is vector format so you can print out at any scale you want (if you have a printer big enough)
Its only a rough drawing at this stage and I didn't have span tables when I drew it so some revision is necessary.
I'm thinking of eliminating the drawn windows in favor of clear polycarb ones between the rafters and having a narrow eaves. This will admit indirect light in around the top of both side walls without losing the wall area of standard windows. This means that instead of solid blocking between the rafters they will need to be strutted herringbone style to prevent the rafters racking.
10th April 2009, 11:34 PM #11
With this design which is a cathedral ceiling with collar ties a ceiling can be fitted on top of the rafters and under the roof/ceiling purlins (ie battens in this instance)
15th April 2009, 11:28 PM #12
I've worked out a price on F17 Hardwood, from the bottom up:
- Posts 150x150x1500 x 15 $867
- Bearers 125x75x3000 x 12 $538
- Floor Joists 125x50x3000 x 48 $1437
- Flooring 100x25x12000 x 30 $1137
- Wall Plates 100x50x36000 x 2 $478
- Studs 100x38x2.4x 60 $727
- Weatherboards $4032
- Rafters 150x50x4000 x 40 $1915
- Ceiling Joists 150x50x6000 x20 $1436
- Ridge Board 150x50x12000 x 1 $143
- Battens 75x38x12000 x 12 $492
$13247 in total. Yikes!
Plus $1600 for Zincalume roof. $14847 all up.
The biggest cost is Weatherboards, solution: Have the shed clad in Zincalume for $600 or so.
Another big cost is ceiling joists. Can I just have shorter collar ties instead?
Rafters are a big cost. I worked out the price with 600mm spacing, can I use 900mm?
Instead of 100mm wide wall plates and studs I can use 75mm wide, correct? That'll save me $376
If I choose the cheapest options the total will be $8844
What size and span can collar ties be?
16th April 2009, 12:08 AM #13
where are you getting your timber from?
The weatherboards are more than double bunnings price for new baltic
16th April 2009, 12:25 AM #14
Without going into span tables and checking things out.
You could use anything from F5 up, F17 is over the top, which is why its high priced.
75 x 38 should be ok for studs and plates if there is a stud directly under each rafter though I like to double my plates as you can get very straight walls with doubled plates.
150 x 50 rafters should be ok at 900 cts maybe even at 1200 cts perhaps even 1800 cts with F17.
An unstrutted ridge board needs to be a minimum 25 wider than your rafters but it can be 25 thick, so you need 175 x 25 for ridge board
You don't need ceiling joists unless you want a low flat ceiling.
You can put a ceiling on top of the rafters cathedral ceiling style.
For coupled rafters with an unstrutted ridge and no underpurlins you will need a collar tie on every set of rafters. 75 x 50 up to 4.2 span, 100 x 50 over 4,2 span.
16th April 2009, 11:26 AM #15
Sounds like an ambitious project you are undertaking But it'll be a good shed once you've finished it. Just thought I'd put across some of my thoughts as I'm in Queensland as well & working in the building industry.
Are you planning to build this yourself mate? From what I gathered you are - any new construction work over the value of $1100 needs to be licensed. Easiest way would be to use someone's builders number - hard bit is finding someone willing to do so. Dunno if you or someone you know is licensed, just thought I'd bring it up.
For overall costs, I reckon there'd be a few more areas to look at. I know you've costed the bulk of the timber and framing materials, but there is also plenty of other costs involved. For example:
- Machine for post holes (would be a dog digging these by hand)
- Concrete for posts
- Fixings - plenty of these....things like bolts for framing, nails for cladding, roof screws, etc
- Access doors
- Electrical (power points, lights, etc)
- Couldn't see anything about internal linings - are you doing that or just leaving exposed frame?
- Drafting fees
- Council fees
- Licensing/BSA fees
- Painting (assuming you'll paint the outside)
- steps up to floor (anything 190mm above natural ground level will require additional steps)
That's a couple of areas off the top of my head that you'll need to look at to get an idea of total cost of the shed.
I'll second what Echnidna about the weatherboard cladding - where are you getting that pricing from? I did a roughie calculation based on using Hardiplank cladding and was about $1500 for the whole shed. Hey about what about something like yellow tongue sheeting for your floor? Would be something like $400-500 instead of $1137 for your hardwood.
Also, make sure that the timber you get is appropriately termite treated as required by BCA & Australian Standards. That is H4 treated for your stumps in the ground, then H2 & H3 treated for the rest of your structural members. Though there are a whole swag of naturally resistant timbers listed in Appendix C of AS3660.1 so if you used them you'll probably be right.
Anyway, just a couple of points to ponder on.
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