Joist hangers for carport

[Adrian]

HI All

Planning on constructing a carport next week... overall dimensions approx 16ft x 19 ft - and it's in a fairly exposed situation out here in the South-west of Ireland.

Have ordered some heavy-duty transluscent box-section sheeting (16.5ft long by 3'2" covered width) - which will mean there's no need for joins along the length of the sheeting. Comes complete with the right socket-head screws for fixing.

Was going to construct the framework with four 4" square posts located in 'Metposts', concreted into the ground, and a 6" x 2" wallplate bolted into the wall, with 6" x 2" timber running along the sides and down the length of the sheeting. All timber pressure-treated.

For ease of assembly, I was going to run cross-pieces of 2" x 2" fixed at right angles to the top of the 6" x 2" to support the width of the sheeting, and then infill along the length of the 6" x 2" with more cut 2" x 2" (saves cutting the 2" x 2" into the 6" x 2")

Any fatal flaws that anybody can see in this plan ??

To fix the 'rafters' to the wallplates I was going to use joist hangers... I noticed one website where it mentioned use of joist hangers with 'engineered nails'...... does anybody know what they mean by this ?

I was planning on using some stout screws, or even bolts.... don't like bashing nails into timber that's bolted to the house wall...

Any comments or improvement to the above scheme gaterfully received !

TIA Adrian

[The Medway Handyman]

I think they mean ring shanks nails (think that's waht they are called) they have sort of corrugations to stop them coming out.

I agree, no point bashing nails in. I use these for fixing joist hangers when building decks

go in with a 14:4v drill driver in seconds. You need the hex drive socket as well.

[Andy Hall]

I'm not a big fan of Metposts for two reasons:

- their fixing in the ground. They have a relatively thin section to ease them being bashed in. However, this is also their undoing since that is able to displace soil more easily if they are moved sideways with the force of a post. However, concreting should address that issue.

- the socket fitting in the top is very short for a post where there is going to be sideways force - i.e. risk of the post breaking at the top of the socket.

This is quite a large area of carport. Unless I've missed it, it looks like you are making a set of rectangular shapes for the framing work and joining them at the ends. Joist hangers are good for supporting the cross members in terms of up/down movement or indeed sliding sideways movement. However, they are less good at preventing the piece joining being pushed out of square.

I don't see anything in the design that prevents the frame structure from twisting if pushed from the end, other than when you have fitted the sheeting. That will possibly be OK, but it is only plastic sheeting. I think on something of this size, I would want to incorporate some timber components that cause triangles to be formed either in the plane of the roof or the verticals and thus prevent distortion of the frame.

These are ring shank nails. I have used them in my framing nailer, but for other parts of the frame than joist hangers.

Fixing of the wall plate is an ideal application for resin fixings.

[John Rumm]

Sherradised square twist nails are the usual thing to use with hangers:

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With hangers you have lots of small holes to nail in many cases. The nails are actually quote small and easy to nail - but you are supposed to nail every hole.

[Adrian]

HI David

Thanks for the reply

Oh right - I know those....

I'll have to see if my local 'Builders' Provider' out here does such a thing...

concerned....

The nearest thing I've got to a pro battery drill is a 24v noname jobbie - but I'm sure it'll do the job. (Only drawback is that it weight a ton - you certainly know when you've been using it for a couple of hours....

Many thanks!

Adrian

[Adrian]

The 'soil' that they're going into out here is probably better described as 'hardcore'. Like many new builds in Ireland, our house is built on a platform 'carved' out of a sloping field - used to be a small stone quarry - so I may well resort to 'fitting' the metpost with the aid a chisel in the SDS drill !

Either way - it will have a concrete casting around it - so shouldn't go very far...

Hopefully not too much of an issue in this application though I take your following points about bracing - hadn't considered that...

Yes - very good point. I guess some 6" x 2" pieces cut to fit diagonally inside the rectangular frames would do the job - just to stop the thing from going trapezoidal on me....

Probably do this at the four 'outer' corners...?

Also something similar to brace the 4" posts to the outer rails ?

Right - never heard them called 'engineered' - but understood. I like the look of Mr Medway's coach screws....

Never used them...... ..not sure I'd ever use them again - so don't know about learning a new technique just for one job....?

I was thinking of something along the lines of these guys

one every metre or so....

There won't be a great loading on these fixings - although the cladding will be relatively 'level' (probably 6" total drop along the 16ft) we don't get snow out here - so the heaviest loading will be a 'roof-full of rain'.....

Thanks for the suggestions

Adrian

[Adrian]

Ah - right !

Yes... Presumably Dave's coach-screws would do the same job ??

Thanks Adrian

[Andy Hall]

Something like that. It doesn't matter too much how you do it.

Another option would be to put in some short timbers of say 500-600mm at 45 degrees between the vertical posts and the horizontal rail that goes across the top of them. I would slightly notch into the posts and the rail to accept the ends and then drill and bolt through with long coach bolts. That would add a little bit of "architectural" interest as well.

If you get a situation where the wind is catching the structure, then there will be less force at those corners than there would be where the joists meet the wall plate.

Yes. A good way, I think.

Very easy.

You buy the lengths of studding e.g. 10 or 12mm in this case and tubes of mortar loaded resin e.g. the Fischer stuff (Screwfix 80157 and

15789).

You need a drill that is 2mm larger than the stud for the wall. Drill the hole and thorougly clean using a vacuum cleaner. Inject some of the gunk. The smaller one doesn't need a gun. Push in the stud, clean off any ooze and leave it overnight. Next day, very strong fixing indeed.

The other advantage is that the condition of the wall or the material is not very important. I have used sleeve anchors in the past. They can be OK, but can also have a tendency to pull out with certain kinds of wall material and condition.

As I say, I don't think it's so much downward force as pull away that is a risk.

[Adrian]

OK

Yes - think that might be a good plan...

That's true - worth bracing all four corners on the 'horizontal' plane, and then the two 'outside' corners in the vertical plane then..

OK - sounds easy ! The structure I'm fixing into is new concrete block with rendering on the outside - should be fairly strong. I guess the resin system would cope well in the unlikely (!!) event of the fixings coinciding with a horizontal mortar line - whereas a sleeve anchor would simply try to prise the joint apart...

Don't know if such a technology has made it over here yet - I'll have to ask !

True.... So it's resin anchors of I can get them - otherwise it'll be sleeves. Thanks !

Rainy day out here today - gives me a chance to plan a job for a change - rather than just rushing headlong into it !

Regards Adrian

[Andy Hall]

Something like that. It might even be worth doing the intermediate posts in the vertical plane.

I think the thing to do would be to put up the framework and see what the result is like. Then add additional braces if needed.

I would have thought so. Fischer products are fairly pervasive in the construction industry.

Raining? I'm shocked ;-)

[Adrian]

Yes - good plan

We'll see.... Sometimes things are a bit 'traditional' out here...

Don't be ! I should have been at the local market today with my stained glass - but one look out of the window at 7am made me think 'Perhaps not today'.

Never mind - it's 'supposed' to be brighter tomorrow for the other market that I go to - so we'll keep our fingers crossed.

And the brand new heat pump that we eventually got installed last week has thrown a wobbler - showing an error that Babelfish interprets as

"The safety temperature limiter STB drew lots"

Ah - so _that's_ what's the matter with it Bank Holiday over here on Monday - so shan't be able to get in touch with the plumber until Tuesday - immersion heater & log fires again tonight !

Ho hum Adrian

[The Medway Handyman]

I use these for 6 x 2 ledger plates, cheap, quick & invredibly strong.

[Adrian]

If only Screwfix delivered to Ireland......

I'll go shopping on Tuesday (Bank Holiday over here on Monday) and it'll probably be a case of 'whatever they've got in stock'....

I was going to use proper bolts to hold the uprights onto the horizontal 6 x 2's - maybe even invest in a drill that's long enough to do the 8" hole in one hit.... it's going to get boring (no pun intended) trying to use my shorter bits....

I guess I could use your coachscrews, if I could get some 4 or 6 inch ones - though instinct suggests that a 'proper' bolt would be a better solution.....

The local sawmills up the road specialises in decent pressure-treated timber - mostly for decking, pergolas etc - and it's a good deal straighter than the stuff that the biulders' provider wants to sell me.

I'm dangerously close to preparing a 'shopping list' !

Many thanks Adrian

[The Medway Handyman]

That's what I meant!

You can bolt them or nail them I believe.

I put one in each side and two on each plate if that makes sense. I do use the 50mm ones Adrian, I posted the wrong link - sorry.

[Adrian]

No problem - thanks for the correction !

Adrian

[The Medway Handyman]

I never realised they didn't. Why would that be? They must be missing out on a large potential market surely?

[Adrian]

Don't call me Shirley !

Well - not that large a market - apparently 4,239,848 men, women and children according to

country - sparsely populated.....!

The giveaway is the bit on the Screwfix website where they ask you to enter your postcode for delivery - out here in the sticks we don't have postcodes.......

Shame - used to like getting my parcels from Screwfix.

Never mind - the benefits far outweigh the disadvantages

Adrian

[John Rumm]

Depends on the hanger. Some will take nails or bolts. Some of the lighter ones like jiffy hangers are nail only.

[The Medway Handyman]

These are apparently nail only but accept to M6 Turbo Coach Screws

?id=63868&ts=10634

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "The Medway Handyman" saying something like:

They have a contract with ParcelFarce (if it's still called that) which only covers the UK and simply can't be arsed to send a parcel outwith that system/contract.

A Customer Service dimbo phoned me a couple of years ago to explain the position and started to bullshit me about PF not having the ability to deliver in Ireland, which I know to be utter rubbish - said parcel is simply passed to the Irish PO.

Lots of other UK companies deliver to Ireland quite happily, some even using ParcelForce, so f*ck Screwfix - it's their loss.