Using Patio Decking Boards as Roof Battens

[brewhut]

Hi folks,

Continuing my brick shed roof after a year’s absence!

See previous thread –
//www.diynot.com/forums/viewtopic.php?p=1729028#1729028


Recap:

Building is 7.8m x 2.6m
Three sides ½ brick with piers, window/door side cavity with brick/block
Final Apex height 2.5m, pitch 10 deg
13 joist (125mm x 47mm) with solid firing on top (250mm – 0mm at 47mm thick) fixed at 600mm centres.
2 gable solid rafters 47mm
Ridge noggins between all rafters
Simpsons JHA timber to timber joist hangers bend over on to wallplates used.


I have finally purchase the metal tile effect roof sheets, Versasteel pantile type, weight is 5kg/m.

The sheets are only 1300mm long and a tile length is 350mm. It needs fixing at the drop of each tile, so 4 battens.

The fitting instructions say batten size 32mm x 100, the tekscrews I have are 27mm long.

I was going to deck the roof with 18mm ply, but the screws would poke through.

I’ve seen some treated decking (type used for patios), its size is 125mm x 32mm at 4.2m long. One side is solid the other grooved. Could these be used as battens ?

Also this would cover 4 x 125mm = 500mm of roof, might as well cover the other (1300mm – 500mm) = 800mm as well ?

I could fix them with the plain side facing out with a 5mm gap between for expansion.
I need 1300mm / (125mm + 5mm) = 10 lengths to do a ¼ of the roof, so 40 lengths in all.

Guess I’d have to make sure a tekscrew didn’t land in a 5mm gap!

They could be staggered i.e 2 at 3.9m joined at centre rafter for full length of 7.8m, then 2.1m + 3.6m +2.1m on next row etc….

Would also leave a gap at ridge for ventilation.

I have the roofing felt (Tyvek Supro) this could be stapled/fixed to plain outside of the decking.
The felt says ideal for metal roofs, can be in direct contact with materials and doesn’t require ventilation. In this case though the eaves and ridge will be left open so air can circulate between roof sheet profile and felt for condensation.

Will also add some DPC fixed at eaves hanging into gutter to provide eaves protection. Double sided butyl tape used to stick felt to DPC


Advantages are:
Thicker than 18mm ply, screw won’t poke through.
Decking can be installed from inside building
Price cheaper than good quality ply
Treated
Easy to cut and manage

Not Sure:
What fixing and size to use, i.e screws, galvanised nails etc..
Weight of 40 x 4.2m decking plus 110kg of roof sheets ?


Are the above ideas feasible ?
Are there any problems with doing things this way?

Any help or suggestions would be greatly appreciated

Thanks in advance

Brewhut

 

[masona]

I was going to deck the roof with 18mm ply, but the screws would poke through.

I'm wondering if you can use nuts/bolts instead of screws and use the some size bolt head for the cap cover?

 

[brewhut]

hi masona, nice to here from you again

I already have 500 tekscrews that self drill the metal also have a load of stitching screws a well. The company worked it out and the sizes to go with the instructions.

Sounds more complex for me (DIYer) to drill roof sheets for bolts

I'm just thinking if I've got to use 32mm x 100mm battens anyway, will decking boards work just as well and can I cover the whole roof as explained

 

[masona]

I'm just thinking if I've got to use 32mm x 100mm battens anyway, will decking boards work just as well and can I cover the whole roof as explained

Can't see a problem with this

Sounds more complex for me (DIYer) to drill roof sheets for bolts

If it was me I would use 18mm plywood maybe osb or shuttering ply for saving cost ( but you get what you pay for) then screw the ply onto the rafters with roofing felt on top with nuts/bolts the metal sheets through the plywood. By using hexagon bolts the exactly same size head as the tek screws by using the same washer and the rubber washer so you can use the tex screws cover cap. If you hit the rafters then use the tex screws

There's no right and wrong way, it's what you prefer to do, I feel the ply will support the roof solid and more rigid with a better finish underneath instead of seeing the felts, you also wouldn't have to worry about hit & miss if you do the batten instead. I can even walk on my roof because of the plywood if need be but it's not important

 

[brewhut]

Masona, thanks for reply.

I see what you mean, but I guess I’d still have drill holes for the bolts.
Is there such a thing as a tekbolt in which case I could go through sheet and wood in one go then put the nut on and saw off the remaining drill part. Any idea how I would attach the ridge and gable barge boards

I originally mention these decking boards because a friend bought a load of 4.2 long ones to do his patio, but he has now decided to flag it and as said I can have them for £2 each, so that’s only £80 for all I need.

The gap would only be 5mm (for expansion as for patio) where you see felt. I was going to cork the gap on the inside for cosmetic reasons anyway. I could have a dry run with some boards and put a sheet on top to see where the screws come out, there will only be 4 of them in total, 3 after each profile drops and the last one at the eaves before fascia. If any get too near a gap I could cut the board width down to shift the gap. I could do with weighing a metre length, then calculate the total weight.

Building is next to boundary and 20.3 sqm area, so has to 2.5m high and made out of non conbustable materials, does the wood in a roof effect this

Thanks again any help

 

[masona]

I guess I’d still have drill holes for the bolts.
Is there such a thing as a tekbolt

You can get hexagon bolts however I've used texscrews into my plywood

Any idea how I would attach the ridge and gable barge boards

Do you mean this?

I originally mention these decking boards because a friend bought a load of 4.2 long ones to do his patio, but he has now decided to flag it and as said I can have them for £2 each, so that’s only £80 for all I need.

That's okay

Building is next to boundary and 20.3 sqm area, so has to 2.5m high and made out of non conbustable materials, does the wood in a roof effect this

This may answer your question,
Buildings exempt from control under the Buildings Regulations 2010

Displayed below are examples of the most common buildings and extensions that we get asked about.

Note: These single storey buildings and extensions are exempt provided they do not contain sleeping accommodation and no electrical supplies (lighting or power) are provided to or within them.

Exempt detached buildings
D1 Floor area up to 15m². Can be built of any materials.
D2 Floor area up to 30m². Must be built of substantially non-combustible materials i.e. Timber doors and gutter facia boards are O.K. as are flat roofs with mineral chippings on felt covering or pitched roofs if they have concrete or clay tiles.
D3 Floor area up to 30m² and at least 1.0m from any boundary. Can be built of any materials.