Corrugated Metal Roofing

[TheMick]

On 12/04/2020 at 14:14, Cpd said:

You would need to detail the insect mesh where it meets the roof membrane and I’m not sure how you would get the rubber in the right place as the first Fixing  batten will be at least 100mm up the roof... just needs a mock up to come up with a plan. 

For the bug mesh could the first horizontal batten be at the bottom of the rafters instead of the 100mm or whatever up? Or is this not advisable for weather and such? 

 

I've done a bit of a digging and this site https://www.steelroofsheets.co.uk/supporting-roof-sheets/

suggest tek screws should not be used in any timber less than 50mm deep.

 

With that  in mind for the vertical and horizontal battens is it best to increase the space underneath the tin to 100mm or just use horizontal battens at 50mm directly into the rafters?

 

Thanks for all your responses. They have all contributed to helping me push on with this. 

Cladco gear all ordered now and going to try and make it like the drawing by CPD but still unsure regarding infills and bug mesh at gutter end of roof. 

Edited April 13, 2020 by TheMick

[Cpd]

8 hours ago, TheMick said:

suggest tek screws should not be used in any timber less than 50mm deep.

I can ASSURE you that screwing into 25mm batten will be MORE than adequate, my roof only has 4 lines of screws and it’s absolutely solid and withstands consistent wind of over 70mph for days on end with gusts far exceeding that. Securing the battens into the rafters is the important bit so don’t be cheep on those fixings, big deep screws are needed. 

[Cpd]

8 hours ago, TheMick said:

still unsure regarding infills and bug mesh at gutter end of roof. 

I will try and mock something up today and take a photo, got to leave my sanctuary and head out Into the apocalypse and dodge the zombies while trying to do the weekly shop.......

[Russell griffiths]

The first thing you needed to do @TheMick was explain what you wanted to build, everything revolves around that, the specification for a 3 storey commercial building will be very different to a single storey building in the corner of someone’s garden. 

Looking for a specification from a website they will be cautious because they think you will fit their sheets to a big barn in an open farm yard. 

I think you mentioned garage so I presume single storey, 25mm battens will be fine, you can get the mesh online it’s stainless steel fly mesh. 

Fit your counter batten then fit the first batten right on the edge, you can staple your mesh to this. 

Use a fixing that is long enough to go through batten and through the counter batten into the rafters that way you are not relying on a 25mm to 25mm fixing so you want a 90mm fixing for the top battens, 

make sure you buy tex screws for wood not metal

look for a vid on how to torque your screws down so you don’t destroy the rubber washers, it’s all in the finger on the trigger control. 

[TheMick]

4 hours ago, Cpd said:

I can ASSURE you that screwing into 25mm batten will be MORE than adequate, my roof only has 4 lines of screws and it’s absolutely solid and withstands consistent wind of over 70mph for days on end with gusts far exceeding that. Securing the battens into the rafters is the important bit so don’t be cheep on those fixings, big deep screws are needed. 

It's just that site is saying 25mm battens can split wothout you knowing i think. 

Is it best to keep the gap to 50mm or could 75mm or 100mm be OK. 

 

I suppose it increases the area for wind to go up so maybe a risk for lifting the roof off haha. 

[TheMick]

Also just found out I can only seem to get 50mm thick treated timber for the battens from both local merchants. 

That would give me 100mm gap beneath the tin sheet of both vertical and horizontal batten on top.

 

That acceptable you guys reckon? Thx

[joe90]

battens come in two basic dimensions: 25 x 38mm and 25 x 50mm. I used the 25 x 50, more than adequate IMO.

Edited April 14, 2020 by joe90

[TheMick]

2 hours ago, joe90 said:

battens come in two basic dimensions: 25 x 38mm and 25 x 50mm. I used the 25 x 50, more than adequate IMO.

Yeah but I can only get 50mm depth buddy hence the question about having a 100mm gap under the tin (2x50mm battens vertical and horizontal) )tah

Edited April 14, 2020 by TheMick

[TheMick]

Mind bloody roof membranes are a bit of a mine field to find which is best aren't they. 

 

I'm guessing the higher the GSM the better? 

[Russell griffiths]

1 minute ago, TheMick said:

Mind bloody roof membranes are a bit of a mine field to find which is best aren't they. 

 

I'm guessing the higher the GSM the better? 

Just get the standard one from the local builders merchants, ask which one they sell the most of. 

[TheMick]

3 minutes ago, Russell griffiths said:

Just get the standard one from the local builders merchants, ask which one they sell the most of. 

Cheers Russ. 

I got the wire mesh you mentioned. Just got 100mm wide in case I can only get 50mm battens. Will cut it if I manage to source 25mm depth. 

[Russell griffiths]

2 minutes ago, TheMick said:

Cheers Russ. 

I got the wire mesh you mentioned. Just got 100mm wide in case I can only get 50mm battens. Will cut it if I manage to source 25mm depth. 

Use the 100mm staple it on top of batten, if you cut it it frays. 

[Cpd]

If you are only going to use one layer of batten with the roof membrane draped between the joists then I think it will be fine as you can get good fixings through the 50mm batten into the joists, it could get quite expensive for fixings if your going for two layers of battens at 50mm and then Into joists. It’s strange that you can’t get the standard 50x25mm roofing batten.  

[TheMick]

2 hours ago, Russell griffiths said:

Use the 100mm staple it on top of batten, if you cut it it frays. 

Thanks for the tip. 

 

What do you make of this Membrane? 

Seems well reviewed. Thx

 

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.amazon.co.uk/SuperFOIL-SFBB-Breathable-Membrane-25m/dp/B00OA9GIB2&ved=2ahUKEwiDzZHDuOroAhW8VBUIHWlGCjQQFjAAegQIAxAC&usg=AOvVaw2WbPln9mZh5pdGu-2gQyjt

[TheMick]

1 hour ago, Cpd said:

If you are only going to use one layer of batten with the roof membrane draped between the joists then I think it will be fine as you can get good fixings through the 50mm batten into the joists, it could get quite expensive for fixings if your going for two layers of battens at 50mm and then Into joists. It’s strange that you can’t get the standard 50x25mm roofing batten.  

Not sure whether it's something to do with covid 19 or what. 

 

Found JMD Building and supplies who seem cheap for treated 25mm but debatable whether they will deliver as have warnings all over site about covid 19 issues. 

[trialuser]

@Cpd. Your roof looks great. I am probably about to change from standing seam to crinkly tin as it's a quarter of the price and my wife really likes it. I see from your photos that you used the type of flat washered tek screw usually used when fixing through the trough of square profile sheets. From my research it seems it is usual to use a fixing with a cupped baz type washer when fixing through the crest of corrugated panels. Can I ask how yours are standing up to weathering, do they seal properly?  Most of the cupped washer fixings I can find are either for fibre cement, or else they wont accept the colour matching cap. Thanks

[trialuser]

Anyone. Have I done whatever is necessary to bring this to the attention of Cpd? I though if you put an @ sign in front of a name they got a notification, is that right?

Thanks

[JamesP]

3 minutes ago, trialuser said:

Anyone. Have I done whatever is necessary to bring this to the attention of Cpd? I though if you put an @ sign in front of a name they got a notification, is that right?

Thanks

@Cpd

[trialuser]

Thanks JamesP ☺️

[Cpd]

On 29/10/2020 at 23:50, trialuser said:

@Cpd. Your roof looks great. I am probably about to change from standing seam to crinkly tin as it's a quarter of the price and my wife really likes it. I see from your photos that you used the type of flat washered tek screw usually used when fixing through the trough of square profile sheets. From my research it seems it is usual to use a fixing with a cupped baz type washer when fixing through the crest of corrugated panels. Can I ask how yours are standing up to weathering, do they seal properly?  Most of the cupped washer fixings I can find are either for fibre cement, or else they wont accept the colour matching cap. Thanks

Hay @trialuser only just seen this..... been securing everything outside as we are in the middle of a good old storm.....  I looked at various fixings and read various reviews and would say without a doubt that the tek screw is the way to go. They are seriously robust, galvanised with a nice chunky thread and WILL not shear or cause you a problem. The washers are perfectly  good a creating a very good seal but as with everything you need to get in the swing of using them. From memory I drilled my holes before screwing down, when you screw down you need to go steady and apply pressure to the tin with one hand while the screw goes in, this stops the tin riding up the thread of the screw (my drilled holes were small, just big enough for the threads to grip but not so big that the screw could be pushed in) the aim is to compress the washer by half but definitely not so it’s squashed flat ! If you overdo it it’s best to take the fixing out and start again (rather that just backing the fixing of a bit) as the washers do not bounce back  after over tightening and a trashed washer is not going to do it’s job. After the fixing is done just give the tin a thump above or below the washer to check that the tin has actually gone all the way down to the batten, you WILL sometimes see that the tin has actually risen up the thread of the washer and the thump will send the tin home and then you can adjust the fixing. Drilling the holes in the tin helps to prevent this and a slightly bigger drilled hole would eliminate this but I did not like the idea of oversized holes..... it’s probably nonsense as if the water gets past the washer then it will work it’s way into the thread  hole anyway...  but in my mind I think a fixing tightly fitted into the tin was better...  so drill, fix, thump.... move onto the next on. The caps are easy to fit, I usually give them a tap with a small rubber mallet just to make sure they are sitting snugly. The fixings are obvious but done well they look really good, get you lay out wrong and you end up with fixings all over the place and it suddenly looks shite....  you really do need to plan where your fixings are going to fall BEFORE putting the tin on the roof. Remember you can loose the top fixings right up at the top of the roof  below the ridge (also these go in the valley of the tin as they are hidden by the ridge) but don’t place them where the rubber weather strip will go.....  ok think that’s it...... 

 

[trialuser]

Thanks very much, very comprehensive. I have used tek screws with square profiled steel roofs and I know exactly what you mean about the thump ?

Did you fix say at the tops and lay half a dozen or so and chalk a line to align the fixings, or use a gauge rod, or how?

I think I'm asking how best to get a decent straight line of screws.

It also hadn't occured to me to fix the row under the ridge in the valley, but makes sense.

I'm glad that the flat tek washer seals well on the curve of the corrugated profile, I didn't fancy removing and replacing thousands of flat washers with the baz ones

One more thing, do you notice any issues with thermal expansion, my roof slope is about 4.2M and black, so potentially the tin could want to try and lengthen by a couple of mm

Thanks again.

[Jonathan Oakes]

Hi Cpd,  I'm glad I stumbled upon this thread. I think the corrugated roof with the Velux looks superb. I have a single story building in Manchester like this, currently used as a photographic studio. It currently has double skin cladding with some diffuser panels for daylight. I want to replace it with roof like yours with clear glass Velux to let plenty of daylight in and has more insulation.

 

My question is what is underneath, how is it finished off visually so the Velux look neat, is there much insulation ?

 

My building has steel trusses and a few cross pieces of angle iron supporting the roof. Could I achieve an effect like yours without fitting timbers ?

 

Thank you so much in advance.

 

Jonathan Oakes

[Cpd]

Good evening @Jonathan Oakes I am a bit brain dead with tiredness tonight so cannot give you a good reply.... 

the main problem is that you have nothing below the tin to fix the velux easily to. 
from what I can see the roof you have is a very light weight design and adding lots of timber, windows  and insulation could cause structural problems. 
as I say to my friends, anything is possible.... it just comes down to how much money do you want to spend on getting there. 
I am afraid that this is probably beyond my field of knowledge. 
maybe @Mr Punter would know of a solution as he deals with more commercial projects I think..... 

if something comes to me when I am not so brain dead I will post again. 
best of luck and sorry I have nothing useful to say. 
cpd 

 

[TonyT]

Additional steelwork off the existing purlins?

[Trw144]

On 12/04/2020 at 11:54, Russell griffiths said:

This is how I would do it 

cover the tops of the rafters with a good quality breather membrane, then a 50x25 counter batten that fits on top and parallel to the rafters then a 50x25 batten fixed on top but at 90degrees to the rafters, 

fit sheets on top

use a ventilation strip at eaves and ridge you want airflow but not bugs. 

 

Those battens are 100x25 and are spaced 100mm apart 

you won’t need to do this, space them how far apart the sheet manufacturers say you need the fixings 600-750mm whatever, remember you won’t be able to walk on anywhere there isn’t a batten. 

mesh at facia level

 

I'm intrigued from these photos to see what your roof finish is @Russell griffiths?