Framing underneath my house.

Framing underneath my house.
I demolished the old walls, had some restumping done 75mm gal posts, and extended the concrete slap along the edges (doweled into the existing slap).
Now I want to put a build it in. I plan on using a timber frame, chamfer board (treated pine 146mm) cladding on the outside, inside I am planning on using plywood bracing with an MDF VJ panelling over the top of that. Not forgetting to add, the breathable vapour barrier on the outside and insulation inside the walls).
Windows and Doors I am considering buying new and hung in frames, for the time I have available and my skill set I thought the extra cost should be worth it?
Materials and Questions
1. Tie bolts for timber framing:
Should I just get a ramset chemical fastener kit and use that to bolt the framing to the slab? – eg spaghetti fasteners for concrete flooring.
- Dynabolts
- Concrete nails, if so any adverse effects on the slab, can I hand nail or get suitable framing nails for my bostik framing gun. Sizes etc
2. Ant capping single sided 113mm x38mm x1.8m lengths. (open to suggestions on this)
3. M10 –T2 treated pine framing, 90x35
4. Breathable vapour permeable sarking, any recommendations for brands, suppliers?
5. Tacks / nails for sarking, size?
6. Tape to join the sarking, brands costs recommendations?
7. Framing nails for a Bostitch F33PT Framing Gun, Size recommendations?
8. Best means of attaching framing to the gal posts? Liquid nails, screws types.
9. Bracing: Is this necessary considering I am framing between gal posts? I was just considering using plywood bracing F22 4.0mm thick, as this will also make a good backing for thin MDF JV panelling to line the interior with.
10. Flashing for around windows, types, ease of application and costs, recommendations appreciated.
11. Nails for chamfer boards, can I use my framer, I read it takes full round head nails the use of a guide rod, where can I get the nails from and what type are they? Or should I get a bradder to do this job?
12. Insulation polyester batts, I don’t like fibreglass batts and these seem cost effective but open to suggestions.
13. All the materials I have forgot about!
Paint Suggestions?
-paint priming?
-undercoat?
-paint undercoat for windows white
-finish white paint to be water based so it does not turn cream in colour?
Should I paint chamfer boards before putting them up?

Brissy,

I'm too many years away from the coal face to answer some of your questions, (like the nail gun ones!) so I'll skip those. (It's nearly raining here, and for lots of reasons, nothing better to do! :wink:

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Originally Posted by BrissyBrew

Framing underneath my house.
I demolished the old walls, had some restumping done 75mm gal posts, and extended the concrete slap along the edges (doweled into the existing slap).

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If you only dowelled the concrete, you have set up a termite path at the join, so you might consider getting a termite company in to advise you on what to do. It seems from the pics that you've built a beam round the perimeter, and filled it in with slab, that will mean a weak point (in termite terms) at the joints, which won't be covered by the ant cap.

The ant caps themselves by the way, aren't intended to stop termites, but to give a visual barrier so you can see them getting in. The little beggars just build trails over the top of the cap and away they go, but you can see that happening!

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1. Tie bolts for timber framing:
Should I just get a ramset chemical fastener kit and use that to bolt the framing to the slab? – eg spaghetti fasteners for concrete flooring.
- Dynabolts
- Concrete nails, if so any adverse effects on the slab

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I'm guessing that you are doing this without a permit. If you had a permit you would have been required to provide these details! If you did, go back to your draftsman and/or ask your building surveyor just to cover your own bottom.

Having said that you PROBABLY don't need too much in the way of fastenings EXCEPT in the bracing walls. The steel posts, if correctly installed and bolted to the timber frame, will provide all the tie down you need, so you are really just locating the studs. I'd use ramset nails, kept away from the edge of the slab.

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2. Ant capping single sided 113mm x38mm x1.8m lengths. (open to suggestions on this)

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See my note above. Should be soldered not siliconed as the termites don't eat through solder.

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3. M10 –T2 treated pine framing, 90x35

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Since the wall is non loadbearing, you PROBABLY only need 70. Get your draftie/engineer to check.

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5. Tacks / nails for sarking, size?

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In the olden days we used to use clouts and bottle top pressings, but now just go and get some of those pressed out things made for the job! They are only there to hold the stuff till the timber goes on.

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8. Best means of attaching framing to the gal posts? Liquid nails, screws types.

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Ramset! BANG!! Finished! :D Check the bracing walls though, they may have specific fixing requirements.

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9. Bracing: Is this necessary considering I am framing between gal posts? I was just considering using plywood bracing F22 4.0mm thick, as this will also make a good backing for thin MDF JV panelling to line the interior with.

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This is not the place to get that answer. The Code sets out quite clearly what is and isn't required. Without a plan, and a bunch of other information NO ONE can give you that advice. It is unlikely that you do not need further bracing. Go to a drafty or engineer.

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13.
Should I paint chamfer boards before putting them up?

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Yes. Prime BOTH sides of the boards with a heavy preferably oil based primer. The finishing coat is best left till the boards are in place, but you can't prime the back of them once they are up. Don't forget to prime the joints as well when you cut them.

Finally.
IF my guess is correct and you don't have a permit, why not? Think about it, when you come to sell a search will soon reveal illegal work. You may be costing yourself big time in the long run. At least get someone to check the work so you have evidence that it was done in accordance with the BCA.

Good luck with all that!

P

Brissy - I was just looking looking at your pics - You are walling in between the steel columns and down the side of the house also??

The first point that immediately came to mind was - IN the event of heavy rain does water cross the slab and rest or move across the position of the proposed stud wall?

If it does you would probably have to build a 100mm concrete or block upturn onto the slab to keep the framing dry. This also provides for a visual inspection point for white ants.

Also based on my own experience of 75mm x 4mm? wall steel columns they tend to be "springy" unless braced. Have you noticed extra movement upstairs (lateral movement) when you rock side to side with your feet? Put a glass of water on the floor and see if the water moves from side to side. It may not be a problem for you becuase the stumps dont look that tall.

doog

I just read your other posts under J- bolts thread. House shakes hey?? ??

Ok you need bracing walls! these have to transfer load sideways through them to the ground. Not necessarily a big deal except you'll have to nail the 4mm bracing ply at 50mm centres along sheet edges and 75mm elsewhere.

I notice from pics that your house is likely to be a 1930's or older Queenslander style. If this is the case - are you putting the underhouse walls back were they were before? This could be an important consideration if you want to stop the house shaking.

In a lot of houses built then and earlier , especially those with vj walls, king studs went through to the bearers and from the top of the king stud the roof framing was braced, purlined, pitched, hung etc. Generally you would also find a stump either under a king stud position or very close to it.

I'm assuming a few things here, but you mention the house shaking freaking the wife out. While i know unbraced SHS columns have resonance (bounce,spring) it generally isnt enough to be creepy.

If your house is built using king studs and you have removed a stump or a piece of wall carrying some of the load then you may be risking things. I have seen this done at least a dozen times and house restumpers and builders miss it. Bracing walls underneath, if not in the right place, won't help the shake.

Doog

Doog,

It's highly unlikely that the original house had walls underneath. If they did they were just filled in between the original timber stumps, which would have provided the bracing.

I haven't seen the other thread, but if there's no bracing between a good few of the new RHS columns, at least in all the corners, the place'd be like living in a jelly bowl! I've also seen too many lifts with undersized beams, or people replacing the existing bearers, which throws out the joists, which in turn were usually way under what today's codes require. Without expert advice from the start..... well it's not always cheaper to do it yourself!

Looks to me as though the slab does have a step down at the edge, but what I said about getting some advice still goes.

Sure we can tell you how to brace it, but without the plans it's not possible to calculate how much it needs.

Cheers,

P

I'd go along with what the other posters have said, particularly midge and his remarks on building approval.
Most of your questions should have been answered on your drawings.

If you have no approval, why not? You are doing a significant structural alteration to your house. Apart from problems with your resale value, you could be voiding your insurance.

That being said, I have not seen ant cap used on a new building in 30 years. We have advanced in that time. The old ant caps were heavy galv. and could be soldered. You will have to get the same stuff, because zincalume can't be soldered.

I have done quite a few build-ins under high set houses, and again I have not seen a timber frame used for at least 15 years. Lysaght steel stud frames are by far the cheaper and better alternative. Very easy to brace. Of course you would have to buy a cheap mig welder and learn how to use it.

Sorry to be so negative.

Bill

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Originally Posted by bitingmidge

If you only dowelled the concrete, you have set up a termite path at the join, so you might consider getting a termite company in to advise you on what to do. It seems from the pics that you've built a beam round the perimeter, and filled it in with slab, that will mean a weak point (in termite terms) at the joints, which won't be covered by the ant cap.

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I have a reticulated termite system layed under the edging, supplied by a professional

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Originally Posted by bitingmidge

I'd use ramset nails, kept away from the edge of the slab.

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these can be hand nailed? or do I need a ramset gun, and what's the risk of damage to the edge.

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Originally Posted by bitingmidge

See my note above. Should be soldered not siliconed as the termites don't eat through solder.

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got it.

Ramset! BANG!! Finished! :D Check the bracing walls though, they may have specific fixing requirements.


Yes. Prime BOTH sides of the boards with a heavy preferably oil based primer. The finishing coat is best left till the boards are in place, but you can't prime the back of them once they are up. Don't forget to prime the joints as well when you cut them.

Finally.
IF my guess is correct and you don't have a permit, why not? Think about it, when you come to sell a search will soon reveal illegal work.

There were approved plans for downstairs, some time ago, however the the building work was not done to those approved plans hence I had to rip it all out.

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Originally Posted by Dirty Doogie

Ok you need bracing walls! these have to transfer load sideways through them to the ground. Not necessarily a big deal except you'll have to nail the 4mm bracing ply at 50mm centres along sheet edges and 75mm elsewhere.

I notice from pics that your house is likely to be a 1930's or older Queenslander style. If this is the case - are you putting the underhouse walls back were they were before? This could be an important consideration if you want to stop the house shaking.

In a lot of houses built then and earlier , especially those with vj walls, king studs went through to the bearers and from the top of the king stud the roof framing was braced, purlined, pitched, hung etc. Generally you would also find a stump either under a king stud position or very close to it.

I'm assuming a few things here, but you mention the house shaking freaking the wife out. While i know unbraced SHS columns have resonance (bounce,spring) it generally isnt enough to be creepy.

If your house is built using king studs and you have removed a stump or a piece of wall carrying some of the load then you may be risking things. I have seen this done at least a dozen times and house restumpers and builders miss it. Bracing walls underneath, if not in the right place, won't help the shake.

Doog

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I will be replacing pre-existing walls.

As far as ant-capping goes maybe I have used the wrong terminology, I was looking at something that would act as flashing/damp course to go between the timber and the concrete. I have had a reticulated terminte barrier applied under the concrete.

Hi BB,

you can use some of that black embossed plastic for damp proof courses that comes in rolls in various widths. I think it is called simply polythene damp proof course. The good thing about the plastic is that you can cut it with a stanley knife or similiar and its easy to trim.

Run a generous bead of sikaflexx sealant along where the bottom plate fits - drop a length of damp course onto the sikaflex and then position the bottom plate. Fix bottom plate down, The sikaflex bed will seal any penetrations of the damp proof course.

If you are using hand driven concrete nails I would suggest predrilling a guide hole straight through timber into concrete with a 3 mm masonry bit ( an SDS type bit is quickest if you have an SDS chuck).

If you are using the T2 pine you will need to seal any cut ends again especially on the bottom plate. No one seems to know what is supposed to be used for resealing the ends though. Hyne timbers recommend using a copper napthate gel - but a builder here on the coast has used sikaflex with great success. The objective in sealing the ends is to keep moisture out and to stop termites sniffing out the timber.

doog

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Originally Posted by Dirty Doogie

Hi BB,

you can use some of that black embossed plastic for damp proof courses that comes in rolls in various widths. I think it is called simply polythene damp proof course. The good thing about the plastic is that you can cut it with a stanley knife or similiar and its easy to trim.

Run a generous bead of sikaflexx sealant along where the bottom plate fits - drop a length of damp course onto the sikaflex and then position the bottom plate. Fix bottom plate down, The sikaflex bed will seal any penetrations of the damp proof course.

If you are using hand driven concrete nails I would suggest predrilling a guide hole straight through timber into concrete with a 3 mm masonry bit ( an SDS type bit is quickest if you have an SDS chuck).

If you are using the T2 pine you will need to seal any cut ends again especially on the bottom plate. No one seems to know what is supposed to be used for resealing the ends though. Hyne timbers recommend using a copper napthate gel - but a builder here on the coast has used sikaflex with great success. The objective in sealing the ends is to keep moisture out and to stop termites sniffing out the timber.

doog

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thanks doog.

I have a SDS chuck so a 3mm bit and what size concrete nails would you recommend to go witih that bit.

Thanks for the heads up on the dampcourse.

T2 pine, i thought it did not require treatment on the cuts but will investigate further

Hi Brissy, I'd go for minimum length concrete nail of 70 or 75 mm . If your bottom plates are 45mm thick go 75mm + , if 35mm thick maybe 65 mm +. You might have to go to a larger hardware supply to get them. A minimum embedment depth of 35mm in the concrete will hold the bottom plate in place nicely - use a minimum of 3 nails per section of plate.


You could also duck out and get some H3 treated Pine just for the bottom plates. This doesnt need end sealing when cut. But again using sikaflex on the T2 will stop any moisture getting in the cut.

Doog

Actually a 3mm SDS bit might be hard to get unless you go to Trade tools or similiar outlet. 4mm are usually the smallest size freely available. Basicaly you want to drill a hole 80% the shank width of the concrete nail. If the concrete nails are 5mm shank then a 4 mm bit is fine.