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Help with new deck close to ground

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  1. #1
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    Default Help with new deck close to ground

    Hi everyone.

    Previously, i was going to get metal frame work custom made for my deck from stratco which was kinda going into a ditch. After consideration for a few weeks, I am going with utemad's advise from earlier and use timber frames since this is the most comman.

    I read the publication by Timber Queensland regarding there recommanded practics for building a timber deck (see link below).

    http://www.timberqueensland.com.au/m...0decks0306.pdf

    www.hyne.com.au/downloads/dih_downloads_v5/<WBR>TDSHEETS/TRADAC/13_decks_on_ground.pdf

    Here is what i have done so far. I have decided to go with the "bearer less contruction" and plan to use treated pine 90X45mm KD RH F5 H3 grade for my joist as the team member from my local bunnings store said that H3 treated is ok as long as it is off the ground.

    I have drawn up a very rough drawing of what i am planning to do (see attach image).

    Now, here comes the stupid questions...
    1. On the recommanded practics, it said that the to leave 40mm gaps between the decking and the house. Is that really necessary?

    2. Is the 90X45mm H3 timber suitable for the job as joist in "bearer less construction"?

    3. How can i get around the air con drainage pipe close to the wall on top of the drain?

    4. When adding the 90X19 merbu decks ontop of the sleeps to add height for the rest of the deck to sit on, is there any problems with doing that?

    Thanks guy, Any comment will be greatly appreciated.
    Attached Thumbnails Attached Thumbnails 18102007162-edit.jpg   deck-plan.jpg  

  2. #2
    Oink! Oink! pawnhead's Avatar
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    Your standard 19mm decking will only span joists at 450crs. Yours are about 580 so it would be a bit springy. It's more conventional to run your boards in the long direction parallel to the house. You won't see the end grain that way either.
    That looks like a sewer gully that the overflow pipe is feeding into. You should have an access panel over it. See this post for the reasons why.
    I'd run the joists in the other direction @ 450crs. Spaghetti and screw joist hangars to the wall, and spaghetti and skew nail them with 3"x 3.75mm galv. nails. Butt them into the sleeper at the correct height and attach with 3" skew nails and joist hangars. They'll be a little bit over span, but I wouldn't worry about it. It will be solid. If you're worried, then you could get a 3metre sleeper, and bury it on edge at the right height in the middle, and nail your joists on top of it.
    From the photo in your other thread, I can see that the sleeper is only 2.4 and it's joined before the end. This sleeper could settle after a lot of people start walking on the deck. It would be a good idea to dig a small pad under the joint, and pour a bit of bagged concrete in there, as well as another spot in the middle of the span. Connect the joint with a flattened out universal framing anchor on the inside face, and put one at each end into the concrete patio and the wall on the opposite side, as well as skew nailing the joint, and into the masonry.
    Cheers, John

    Short Stack (my son's band)


  3. #3
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    Thanks pawnhead

    Quote Originally Posted by pawnhead View Post
    It's more conventional to run your boards in the long direction parallel to the house. You won't see the end grain that way either.
    What exactly do you mean that it is more conveniet to run board parallel to house? I have drawn up another plan with joist running parallel to house and it looks like its more work?

    I have another problem too, I have already got the 90x45mm H3 F5 joist cut to 2.90m and all of the merbu from bunning that i have picked-up from bunnings is 1.8m long too. Looks like i am stuck with the old plan. Hopefully by adding a joist, I should be able to get away with it in terms of getting it more stable.

    Quote Originally Posted by pawnhead View Post
    It would be a good idea to dig a small pad under the joint, and pour a bit of bagged concrete in there, as well as another spot in the middle of the span. Connect the joint with a flattened out universal framing anchor on the inside face, and put one at each end into the concrete patio and the wall on the opposite side, as well as skew nailing the joint, and into the masonry
    .

    Sorry, i am a bit confuss, can you please clearify? When u refer to the joint, which joint are you refering to??

    Thanks again.

  4. #4
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    here is the new plan with joist parallel to house.
    Attached Thumbnails Attached Thumbnails deck-plan-new.jpg  

  5. #5
    A Member of the Holy Trinity silentC's Avatar
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    If I was you, I would pave that. Seems a lot of effort to go for a such a small area.

    What exactly do you mean that it is more conveniet to run board parallel to house?
    He said 'more conventional' not 'more convenient'. Conventional just means that's what people normally do. It would look better (in my opinion) if the end grain is concealed and you are not looking along the gaps between the boards. The front board will conceal the timber framing underneath.

    But, as I said, if it was me, I'd pave it. Would solve the majority of your problems.
    "I don't practice what I preach because I'm not the kind of person I'm preaching to."

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    A Member of the Holy Trinity silentC's Avatar
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    Thought I'd better give my reasoning:

    1. Pavers are cheaper and quicker. Merbau decking runs to around $49.50 per sq. metre. Then you have to buy the joists, nails, hangers and other sundries. You have to build the frame and then you have to lay the deck. Large format pavers can be had for $40 to $50 per sq. metre. Brick pavers are cheaper still. All you need is a couple of barrows of sand or crusher dust, a screed and a broom. You could knock it over in an afternoon.

    2. Decking needs to be oiled constantly to keep it in good condition. Pavers are forever. They're also more forgiving of the mess that a BBQ can make.

    3. You are creating a damp spot right next to your house with no access. Termites love that.

    4. You have no access to the underside of the deck, so anything that falls between the gaps will stay there.

    In my opinion, close to the ground indicates pavers, elevated indicates decking.

    If you do go with the decking, I'd suggest leaving a gap between the wall and the decking so that termite inspectors can see in there and you lessen the likelihood of termites being able to bridge from the timbers and into your walls.
    "I don't practice what I preach because I'm not the kind of person I'm preaching to."

  7. #7
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    Thank Silent C

    There really quite a lot of factors to think about on this one, especailly after your comments. As you can see, I have already put pavers in and actually left that spot later on for decking not knowing that it would be quite a up-hill battle. I was kinda looking forward to put some feature on the deck too so that it would look good from inside or outside the house.

    I had be quite concern regarding the terminte issue before plus the being so close to the floor does not really help not to mention the problem with drainage pipe. Maybe I should have stick to the metal framework instead.

    I am going to re-think and weight out what i should really do. Better to waste the few dollars that i have spend on the material then to have problems down the track.

    I might also contact someone from timber QLD to get their feedback too and post what they recommand as well.

    thanks guys... any further comment is appreciated.

  8. #8
    Rigid Member UteMad's Avatar
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    Had we have looked at it as a job we would have run the decking pararllel to the house... You will need another joist running it your way as the centres are too wide and the decking will flex.. You should also bear in mind that a 90 x 45 f5 is only rated to 1300mm over a continuous span for decking....so you should have more pad footings too... we would have tried to use 140's if possible cause they would go side to side with one support in the middle

    cheers utemad

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    Quote Originally Posted by samchuang33 View Post
    I have drawn up another plan with joist running parallel to house and it looks like its more work?
    That looks better. It’s a question of taste, and most people, myself included, would prefer the look of having the decking boards running in the long direction, starting with the first board @ 3.15mm away from the wall of the house. The ends of the boards will be against the slab and you won’t see them.

    Screw your decking down so that you can unscrew that first board annually for termite inspection. Use shorter lengths over the sewer gully so that they can be easily unscrewed if your pipework blocks up. If the plumber can’t get his eel around the P trap in the sewer gully, then you can unscrew more boards so that he can dig the whole thing up and remove it for better access to clean out your sewer line, before replacing the gully again.

    If you can't bend the overflow pipe under the decking, then cut the pipe, get two straight connectors, cut the spout off the end, and use that to extend it down. If it's PVC pipe, then you'll only need one connector. Cut it next to the elbow, paint some of the PVC adhesive that you'll need on the inside of the pipe and set it alight. As it burns, prise out the pipe stub and remove it from the elbow. You can then glue the spout that you've cut off directly into the elbow.
    Quote Originally Posted by samchuang33 View Post
    I have another problem too, I have already got the 90x45mm H3 F5 joist cut to 2.90m and all of the merbu from bunning that i have picked-up from bunnings is 1.8m long too. Looks like i am stuck with the old plan. Hopefully by adding a joist, I should be able to get away with it in terms of getting it more stable.
    So you’ve had the joists cut to length. I’m assuming that you have your own saw, drill, and hammer, but if you don’t, then hire a chippie to do the whole job for you. It’s the easiest way out.
    But if you’ve got some tools, then don’t set out your joists at 480crs as shown. Set out your first joist @ 422.5 ‘in & over’, then set out the rest of your joists @ 450 ‘in and over’ i.e. hook your tape on one and measure to the same side of the next so that they are @ 450crs i.e. 450mm from the centre of one to the centre of the next one. By setting out your first joist centre 22.5mm less, then your boards @ 1.8m long will reach to the centre of the fifth joist along. Don’t joint them all there or it will look shocking, but with your joists @ 450crs, all of your boards will span from the centre of one joist to the centre of a joist four spans distant. Cut a poofteenth off the end of each board if necessary, so that your joints are square and tight. You will end up using one extra joist than you have on that plan, and the last spacing will be narrow. Because of this you will have some off cuts from your decking boards and you may have to buy an extra stick or two. You may be lucky and you’re off cuts will be minimal, but I’m not about to calculate everything to that degree. If you’ve got lots of spare time to waste, then you could plan out each board and the off cuts to get a nice random pattern. A chippie would just allow 5>10% waste and attack the job with randomly spaced joints.
    .
    Order a 3m sleeper (you can get them to cut it to 2.9 if you want) H4 treated so that you can bury it in the ground with the top at the level of the bottom of the joists as shown on your plan. Cut the four joists that you’ve got, to span in between the wall and the existing sleeper. With the four off cuts, join them in the middle over the new bearer. With the joint, make it a vertical 45 degree angle over the middle of the bearer. This way they will be easy to nail together with some 3”galv nails, they will both have good support by the bearer, and they’ll line up so that your deck screws will be in a straight line. Then buy two more lengths @ 1.8 (you can get them to cut them to 1.74 less the thickness of the existing sleeper, if you want) to make up your shortfall.
    Quote Originally Posted by samchuang33 View Post
    Sorry, i am a bit confuss, can you please clearify? When u refer to the joint, which joint are you refering to??
    I’m referring to the joint that you can see in this picture. That sleeper is just a 2.4m edgeboard that’s been joined with a short length, and it may settle and move around. It should be treated for in ground use, so I wouldn’t bother with any galvanized posts.
    I’d just lever it up to the right height, so you won't have to put a packing board on top of it, then dig a small pad and pour half a bag of concrete under the joint, and use the other half bag in the centre of the longer length (allow it to set before installing your joists).Then screw a universal framing anchor (sometimes called a ‘multigrip’) at each end of the existing sleeper, into the masonry using spaghetti. With a hammer, flatten out another multigrip and nail it over the joint in the sleeper so there’ll be no movement between the two. Put them on the inside so that you don't see them. Use spaghetti and screws to fix your joist hangars to the wall, and use spaghetti and 3" x 3.75mm galv BH nails on a skew through the joists into the masonry, starting at the edge of the joist hangars.

    If you’re after some special “feature on the deck too so that it would look good from inside or outside the house”, then you could put a diamond in the middle out of a different species of decking boards, if you installed some noggins between the joists. You could run them in a perpendicular direction with a perimeter board. e.g.
    Quote Originally Posted by UteMad View Post
    90 x 45 f5 is only rated to 1300mm over a continuous span for decking....
    That little eh? It would be even less for a single span then.
    Cheers, John

    Short Stack (my son's band)


  10. #10
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    SAMCHUANG,

    Where is the finished height of the decking going to be?

    You see those weep holes under the window - they have to be exposed otherwise you have a termite/ insect breach point . The reason a gap is left around decks where they meet a wall is so any termite activity trying to get from decking to the house can be seen.

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    WOW

    Thanks again pawnhead. That is great help!!! You pretty much planned out the whole project for me to follow. Can't thank u enough.

    I will drawn up a new plan with what you recommanded tomorrow. One thing that did occur to me just now, the distance of the drain pipe is 40cm away from the concrete tile and is 24cm in diametre. I think that will actually be below where the first joist will be. I was going to raise the drain pipe up to the same level as the finished decking therefore it will it could become a problem.

    Anyway, I draw something up tomorrow and see if i can get around it.


    <O</O

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    Quote Originally Posted by Dirty Doogie View Post
    SAMCHUANG,

    Where is the finished height of the decking going to be?

    You see those weep holes under the window - they have to be exposed otherwise you have a termite/ insect breach point . The reason a gap is left around decks where they meet a wall is so any termite activity trying to get from decking to the house can be seen.
    Hey Doogie

    The finish decking will be just below the weep holes. I am aiming to get the finish decking board at the same height as the concrete tiles.

    Considering what you said, it'll be a good idea to incoperate the 4cm gap between the wall and decking that is recommanded by Timber QLD's recommanded practics when i do my plan again.

    Thanks

  13. #13
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    Quote Originally Posted by samchuang33 View Post
    One thing that did occur to me just now, the distance of the drain pipe is 40cm away from the concrete tile and is 24cm in diametre. I think that will actually be below where the first joist will be.
    Well it wouldn't matter if the first joist was a little bit more than 450 from the concrete. Just make sure that the next one along is 900mm from the concrete to the centre of the joist, then go 450crs from there. The idea is that your boards will all join in the middle of the joists with no waste. If you make that joist 900mm from the centre to the centre of the joist that's fixed to the concrete, then when you start your decking board against the concrete it will only reach to the edge of a joist instead of the centre and you'll end up with a big offcut. With the rest of your joists @ 450crs, you can join your boards anywhere and they'll cover four spans with no offcuts.
    Quote Originally Posted by samchuang33 View Post
    I was going to raise the drain pipe up to the same level as the finished decking therefore it will it could become a problem.
    Is the internal floor level higher than the deck? Technically, the gully must be a certain distance below your internal floor level, but I'm not sure how much. You'll notice that yours has a collar that raises it above the ground level as well. I think it must be a minimum 50mm above a deck but I'm not sure. There's a few plumbers on the forums that you could ask if you posted in the plumbing section. If there's another gully around your house somewhere then you may not have to follow those rules.
    Here's a copy/paste from the post I linked above;
    Quote Originally Posted by pawnhead
    A plumber here in the East told me that they must be accessible, and you can't build a deck over them. If anything blocks up, then you'll need to get to it to clean it out. A plumber can get an eel around the bend to clean out the whole line from a gully. He told me that they should either be relocated, or extended up, however they also must be a certain distance below your internal floor level so that if the water boards main blocks up, and backs up, the stuff that comes out won't flood your house through your bathroom floor waste. But they also must be a certain distance above a solid deck so that any overflow has a chance to run away. He also told me that it's illegal not to have one installed, for the same reason. The shyte will have nowhere to go but up into your bathroom or laundry. Of course there could be different regulations over there, or you could be on a septic, not even connected to a main, and it could be there just to catch some tap water, but then I can’t see a tap over it. It does need to be charged though, i.e. it needs to have fresh water run through it periodically so the water in the trap doesn't stagnate, and in case it all evaporates. This is generally achieved by putting a tap over it. In your case it looks like that waste pipe over it does the job.
    I suppose it would be alright to put a removable hatch over it to save relocating it. There's a few plumbers on the forums that you could ask if you posted in the plumbing section.
    Quote Originally Posted by samchuang33 View Post
    Considering what you said, it'll be a good idea to incoperate the 4cm gap between the wall and decking that is recommanded by Timber QLD's recommanded practics when i do my plan again.
    That's a big gap. I could see that the weepholes were on the next course above so I didn't recommend it. I don't see why you'd need it, and I wouldn't do it, but meh.

    Don't forget to post pics of the finished product.
    Cheers, John

    Short Stack (my son's band)


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    Quote Originally Posted by UteMad View Post
    Had we have looked at it as a job we would have run the decking pararllel to the house... You will need another joist running it your way as the centres are too wide and the decking will flex.. You should also bear in mind that a 90 x 45 f5 is only rated to 1300mm over a continuous span for decking....so you should have more pad footings too... we would have tried to use 140's if possible cause they would go side to side with one support in the middle

    cheers utemad
    I have did some research on the treated timbers H3 F5 that bunnings has been sellling (see below link from timber.net)

    http://www.timber.net.au/documents/d...of_F7_Pine.pdf

    I am guess that this is what Utemad was getting the information from. What I am proposing to do now is to go back to bunnings and pick up the 140mmX45mm treated h3 f5 timber deck just to be safe. With the original three 2.9m 90X45mm that I have already cut, I think I will cut them down to 1.7 and join them parella together and use it as one joist just to keep the wastage down. I can't think of any other ways to use them and bunnings will not take them back as it is already cut down. 140x45mm should span 2300mm single span therefore I can also get away with the sleepers in the middle of the joist.

    I have also called brisbane city council regarding the council requirement for decking and they asked me to get a building surveyor to inspect and submit the application form to council. However, the company i called up said that as it is only 5m2, it is too much of a trouble to waste $990 and submit a plan with council. Usally if the area is over 10m2, council approval is required. Is this the case???? If it is, then good news for me i suppose.

    Back the the termite problem that I is still troubling me.... I have also got in contact with the ppl at Terminmesh which did the termite protection for my house. Still waiting to hear back from them. I was thinking maybe I can get some terminmesh to put between the ledgers and the wall just to keep the body corp happy that I have taken extra steps to prevent termites.

    Gee... this is much more time consuming than I thought. Stll haven't hammered anything yet. I hope I can get it done before Christmas

    Thanks everyone for you comments.

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    I have went back to bunnings and exchange all of the deck @1.8m to 3.0m and brought a sleeper at 200X50X3000 for support in the middle of span.

    I am thinking of placing the sleeper flat. That way i do not have to dig down 20cm and also being flat, the span distance will be shorter therefore more stable. Is this a good idea??


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