What fixings may I need to stop leaks?

[David001]

Hello everyone.

The roof of our outbuilding is of the metal industrial kind shown in the pic below.

Last winter there were four wet spots on the ceiling below this roof showing that water had leaked in.

So I can only imagine that the water got in through four of the fixings which hold the roof in place.

The outbuilding was erected 12 years ago.

Is it possible that some of the fixings have deteriorated, so as to let in rainwater?

If so, I am thinking that perhaps I may be able to replace them myself, provided it's not difficult to do.

Are there things I will need to be careful to do, and not do (beside falling off the roof!)?

Or will I need to ask a roofer to do it?

 

Thanks!

David.

 

 

 

 

 

 

 

Edited June 13 by David001
Better clarity.

[Tom]

If that's an actual picture of one of your fixings, and not just a picture from the net, then it doesn't look like it's tight enough against the panel. The EPDM washer needs to be snug but not crushed.

Edited June 13 by Tom

[ProDave]

2 comments, hope they are not harsh, but whoever put that roof on did a poor job imho.  Firstly none of the fixings are in line, that shows a lack of care.  Secondly, I always fix that sort of roof on the ridges.  Little water flows down the ridges, it falls into the flat valleys and runs down there, so you don't really want fixings in the flat valleys where there is more water and more chance to leak.

 

Agreed the one photographed close up does not look very tight.

[Mr Punter]

I would keep the fixings you have and tighten them a little, so the washer is snug on the sheet.

[David001]

Thanks, everyone above, @Tom, @ProDave, and @Mr Punter, for your comments and advice. 

 

Yes, the man who put up that building, and who put its roof on, was a shoddy worker.  It was a DIY job by a man who had spent his working life in an office, he then retired to the countryside, and was certainly confident that he could do all sorts of things.  He had a lot of confidence, but in so many places around this property I've come across evidence of really shoddy decision-making and substandard workmanship.

 

I zoomed in one of the fixings for the close-up without having decided which particular fixing to focus on.  It seems from what you have said that I luckily focussed the camera on a fixing which shows the washer is not flush against the panel as it should be.

 

So it seems that as soon as there's a warm dry day I ought to get up on the roof with a spanner and tighten each head so the washers are snug on the sheet, and then see whether there is any leaking after that.

 

1. Are the fixings above the EDPM washer made of plastic or metal?  

 

2. If while I am checking them all and tightening them some of them break, are they standard?  What would I look for online to order replacements, please? 

 

3. Do I need to be careful where I put my weight?  Where would be best to place my feet?

 

Thanks.

[dpmiller]

probably a plastic cap pushed over a tek-screw

[Tom]

1 hour ago, dpmiller said:

probably a plastic cap pushed over a tek-screw

Yep, I second that. Just flip the cap off with a screwdriver and then pinch the tek-screw up. Quicker and easier to use an impact driver than a spanner, but make sure you don't overtighten and crush the washer.

[saveasteading]

Hooray something I know about.

The screws are rather randomly fixed. Several areas seem to be missing fixings altogether, so the sheet is not properly fixed down and may disappear in a gale.. Crowns (the 'up' bits are screwed just a few times.)

The close up of a crown is unlikely to be a culprit as not much water will reach it compared to the ones in pans.

At least one of the plastic caps is not flush with the sheet. They are not seals, and only for show, but it suggests that the screws are not tight.

Some of the screws  may have missed the purlin, which is likely only 40mm wide.. They would have no purpose but have made a hole and will not have pulled tight.

 

Mark the floor where the drips land as you will forget. You only need to tighten 4 screws at most.

Drips can be direct from screws or they run either down the panel or along a rail to the lowest point. From this you can narrow the search area down to a few screws and fix the ones that need it.

The tops of washers are usually aluminium. The rubbery bit will seal against the cladding in a primitive washer, or squeeze into the thread in a classy one.

Apart from not being quite 'home' the other likely issue is when the screw has spun and the hole is too big, and the screw not gripping.

 

For  a bodge you take the screw out, squirt some mastic in and replace the screw, or use a new one. That lasts a few years and may be what is causing the problem.

For  a proper job, you need a screw with a wider diameter as it will cut a new thread and grip properly. We called them 'repair screws', but I don't think it is a common term. These don't need drilling heads as the hole is already there.

 

The screws are turned using a Tek head.  It is just a hex head but is the right size. Use a clutch drill to avoid over-tightening.

It is worth getting these screws and heads from a  specialist fixings supplier. 

 

Having written that I realise there are lots of possible problems, but just one proper solution. If a simple tightening doesn't work, then replace each (four?) with a slightly wider tek screw. Or just do that anyway.

Be aware that more screws may also fail in time.

 

There will be more errors than just the screws but if it is working I guess you live with it.

 

You don't need new caps but it probabaly looks better with them.

 

Plus. Don't fall off the roof, and don't lay your drill down or it will slide away.

 

 

 

 

[David001]

Thanks, everyone.

 

@saveasteading, marking the floor where the drips land is good tip!  (I took photos of the four wet spots on the very wide ceiling but your method will be much more helpful.)

 

Is that black hexagonal top just "for show"?  

 

Is everything in pic 3, above, just a "slip-on" head with a washer beneath it protecting a screw? 

 

If so, should I prize off by inserting a screwdriver underneath the washer, or between the head and the washer?

 

I'm just a 70-yr-old homeowner ho can attend to basic repairs.  My tools are no more than a range of spanners, screwdrivers, hammers and other basic items.  I don't know what a "clutch drill" is. 😁  Can I remedy the situation with the tools I have?

 

THANK YOU.

 

David.

 

 

[saveasteading]

 marking the floor where the drips land is good tip!  (I took photos of the four wet spots on the very wide ceiling but your method will be much more helpful.)

 

Is that black hexagonal top just "for show"?   The plastic caps are for show.

 

Is everything in pic 3, above, just a "slip-on" head with a washer beneath it   protecting a screw? No

 

If so, should I prize off by inserting a screwdriver underneath the washer, or between the head and the washer?

prise off the plastic cap and leave the washer alone until examined

 

I'm just a 70-yr-old homeowner who can attend to basic repairs.  My tools are no more than a range of spanners, screwdrivers, hammers and other basic items.  I don't know what a "clutch drill" is. 😁 I should have said  torque settings perhaps Can I remedy the situation with the tools I have?

Yes. if the screws only need tightening then a socket spanner will do it. it will only need a half turn or so.

To replace I'd suggest a battery drill is almost essential. most have torque settings.  Borrow one?

A socket spanner might do it?

 

Im not recommending this but, in a push I have used a ladder , tied on to the gutter and 3 rungs past, in line with where I want to work. then if I was to slide, the ladder should provide restraint.

Of course you really should have  a scaffold to access and to catch you.

 

the screw on the right has a plastic cap on it, as left.

If you have a specialist fixings shop near then I'd recommend going there. Even for a tiny order they are likely to be very helpful, and they will have a variety of thread sizes. You will not need that self drill point.

 

 

[Conor]

90% sure you'll just need an 8mm spanner for the screws. 

[George]

 

14 hours ago, saveasteading said:

Hooray something I know about.

The screws are rather randomly fixed. Several areas seem to be missing fixings altogether, so the sheet is not properly fixed down and may disappear in a gale.. Crowns (the 'up' bits are screwed just a few times.)

The close up of a crown is unlikely to be a culprit as not much water will reach it compared to the ones in pans.

At least one of the plastic caps is not flush with the sheet. They are not seals, and only for show, but it suggests that the screws are not tight.

Some of the screws  may have missed the purlin, which is likely only 40mm wide.. They would have no purpose but have made a hole and will not have pulled tight.

 

Mark the floor where the drips land as you will forget. You only need to tighten 4 screws at most.

Drips can be direct from screws or they run either down the panel or along a rail to the lowest point. From this you can narrow the search area down to a few screws and fix the ones that need it.

The tops of washers are usually aluminium. The rubbery bit will seal against the cladding in a primitive washer, or squeeze into the thread in a classy one.

Apart from not being quite 'home' the other likely issue is when the screw has spun and the hole is too big, and the screw not gripping.

 

For  a bodge you take the screw out, squirt some mastic in and replace the screw, or use a new one. That lasts a few years and may be what is causing the problem.

For  a proper job, you need a screw with a wider diameter as it will cut a new thread and grip properly. We called them 'repair screws', but I don't think it is a common term. These don't need drilling heads as the hole is already there.

 

The screws are turned using a Tek head.  It is just a hex head but is the right size. Use a clutch drill to avoid over-tightening.

It is worth getting these screws and heads from a  specialist fixings supplier. 

 

Having written that I realise there are lots of possible problems, but just one proper solution. If a simple tightening doesn't work, then replace each (four?) with a slightly wider tek screw. Or just do that anyway.

Be aware that more screws may also fail in time.

 

There will be more errors than just the screws but if it is working I guess you live with it.

 

You don't need new caps but it probabaly looks better with them.

 

Plus. Don't fall off the roof, and don't lay your drill down or it will slide away.

 

 

 

 

Can I just check my understanding... for square sections you don't put fixings through the crown, only tight into the flat sections. For corrugated roofs it's the other way around and the fixings only go through the crowns.

[saveasteading]

52 minutes ago, George said:

for square sections you don't put fixings through the crown, only tight into the flat sections. For corrugated roofs it's the other way around

On old agricultural corrugated cladding, asbestos or galvanised, it was fixed by hook bolt from on top of the crown, to under the purlin.

 

For modern cladding, which you are calling square, there are screws through the bottom/flat/ pan, directly into the purlin (or first through a skin of insulation) pulling it all tight.

There are still some screws on the crowns to link the edges of adjoining sheets together.

 

there should be mastic tape at these joints in most situations, to keep out water and draughts.

 

If I wanted to fix corrugated cladding 1.  I would question the choice. 2 it would be through the crowns but it would need special screws to resist the cladding ripping down over the thread. These have an additional coarse thread under the washer that should hold the sheet up if it gets stood upon. These are 'stand-off' screws but I wonder how commonly they are used.

[George]

Thanks - didn't know about the lap screw. 

 

Corrugated fibre cement is still a popular choice for ag buildings.

[joe90]

8 minutes ago, saveasteading said:

These are 'stand-off' screws but I wonder how commonly they are used.

I had not heard of those!!!! With my similar workshop roof I used tek screws on the flat sections and short ones on the crowns to hold the sheets together only (Cladco who supplied the sheets supplied info on how to fix). The only thing I did different was to use a membrane under the battens (like a tiled roof) to stop leaks or condensation in the building (worked very well).

[David001]

@saveasteading, thanks for all your answers. Your 2 photos have made things clear.

 

Thanks also for the tip re. using a ladder as a potentially helpful obstruction.  I will tread carefully! 

 

David.

 

 

[David001]

@saveasteading, it's been a busy summer for me and only today have I finally put up a ladder to the roof referred to above and investigated the nearest fixing.   Then coming back to your information and images (above) has been most helpful, because your information now makes sense to me.

 

I prized off the plastic cap and saw the metal hex head.  I gave that a few anti-clockwise turns with a spanner and then discovered that the round metal washer and a rubber washer are separate from the screw.  At first it seemed that the metal washer and rubber washer were fused together, but this must just be the effect of pressure and time.  It seems to me that the black rubber washer is so much thinner than the one in your image, above, and in similar images of such screws on the web.  Is it likely that the rubber washer shown in my photo below has become thin over time?

 

For this kind of roof is it correct that each hex screw consists of four parts: the screw with its hex head, a metal washer, a rubber washer, and a plastic cap?

 

Would it be unwise for me to remove the screws suspected to be letting in water, change their rubber washers, and then screw them back in?

 

Are rubber washers supplied separately for these hex screws?  If so, then as there seem to be different sizes of these hex screws, I would need to find out what size the screws which have been used are.  The diameter of the lowest (round) part of the plastic cap is 2cms, or perhaps 19mm, but perhaps that won't help identify the screw.

 

Thank you.

[dpmiller]

the rubber washer is bonded to the metal one

[saveasteading]

As @dpmiller says.

When squeezed the right amount, the washer will compress and expand into the screw thread.

You should see a slight bulging outwards, much as you show. except that yours is wider to one side only.

The likeliest problem is overtightening / not in straight.

 

With the screw system I used, you would normally not replace that screw with another the same, on the basis that the thread it had cut in the panel or purlin might be damaged. 

Instead we used a 'repair' screw, which had a wider shank and coarser thread. It did not need to be self drilling as the hole is there.

This also allows for the case of a mis-drilling.

 

Do not be tempted to use a big washer instead. the vital element is the inner contact from rubber washer to screw.

 

BTW the coloured cap is only for aesthetics and to protect a carbon screw from rusting. 

 

When looking for a failed screw, I would often find that the cladder had bodged the job and the screw was not gripping properly, and that he had then put some mastic (tube or tape) in the hole as another bodge, before the screw.. They knew very well that this was wrong and didn't get another contract.

[David001]

@saveasteading, many thanks for your above advice.

 

I have taken out one of the screws, as in the two pics below.

 

Without the plastic cap, the total length of the screw (from top of the hex head to the sharp tip of the shank) is 3.7cm.

The outer width of the thread on the screw (directly under the washers) is either 6mm or 7mm.

The diameter of the plastic cap is 1.9cms.

Is this a screw which is well-known?

 

Bearing your advice in mind, I think I need now to find a supplier of similar screws which are 3.7cm in length, but which are 7mm or 8mm in diameter at the widest part of the shank.  Would that increase of just 1mm be sufficient?

 

When you recommend a coarser thread for the "repair screw", does that mean a shank which has slightly fewer "rings" forming its thread?

 

An USA page includes the following:

"a neoprene washer (already light years better than traditional rubber) . . . is independent from the screw head allowing overcorrection during install. They also have a slightly larger and slightly domed metal washer stacked on top which creates an umbrella for the neoprene that guards it against the UV rays that cause cracking. We are seeing screws that at this point can live roughly 50 years if not longer without failed washers. Some companies are now even offering screws with oversized heads and washers with military grade strength that are guaranteed for life"

Are neoprene washers available here in the UK?  Although the roof would look a bit peculiar with only a handful of its caps being of a different kind and size from the rest, maybe I should use them anyway.

 

I live 90 minutes' drive from the nearest big town, so unfortunately I can't easily visit a specialist fixings shop.  Can you recommend a helpful online supplier?

 

Thank you.

 

 

 

 

Edited September 3 by David001
Additional question.

[saveasteading]

29 minutes ago, David001 said:

repair screw", does that mean a shank which has 

Wider and a steeper thread so that it forms it's own thread in the hole.

 

The screw you have surprises me. Most have self cutting points.  Yours have needed predrilling.

 

The first 3 or 4 turns are only for cutting its way in. The others can grip the sheet.

Yes 1mm more will do.

The heads will be standard, as will thecaops in size and colour.

Roof screws are a product where buying the big brands is worth it. SFS  is prob the biggest. Ejot too.

 

I got my sfs screws with the buildings. 

For odds I  would contact Southern Sheeting. Decent people. Not that your order is going to excite anyone.

[David001]

@saveasteading, thanks.

 

I should have photographed my screw from another angle to show the gash in one side of the bottom of the thread, which I think is the "self-cutting point" you have referred to.

 

At several online stores I haven't found a Tek screw with a width larger than 6.3mm.  There's smaller (5.5mm).

 

I have found that there are replacement washers for Tek screws for sale, and some are the right size for my existing screws, but so far I've only found them with "bonded rubber" rather than "bonded neoprene".  What would be the disadvantages of only replacing the current washers with these (i.e. using the same screws as have already been used)?

 

The number of "turns" or "rings" in the thread of my screw is 12. 

Fastco.co.uk offers a same-sized screw with a neoprene washer but 14 turns in the thread.  I imagine this is not a "coarser" screw?

Tcfixings.co.uk offers a same-sized screw with a rubber washer and 10 turns in the thread.  So is this "coarser" than my screw, even though it's not wider?

 

Thank you.

 

 

 

 

 

 

 

[saveasteading]

On 03/09/2024 at 17:07, David001 said:

rubber washer

I don't think anyone uses rubber, but continue with the term.

 

On 03/09/2024 at 17:07, David001 said:

is the "self-cutting point"

I have really only just noticed that the screw you show is on top of the crown. this is going only through two sheets of cladding and is not structural. It is a stitching screw.  It is unlucky to get a leak there . The gash will help cut through but i suspect it needed a drill first. 

The screws running in a horizontal line are holding the cladding down on the galvanised purlins  and will be different to  yours shown. Any of them a problem

[David001]

@saveasteading, a Technical Advisor at Ejot has advised that they don't offer any TEK screws wider than 6.3mm, and I haven't noticed larger ones on other sites, so I'll order new 19mm washers+neoprene, then just take the screws out, change the washers, and then carefully put the screws back in.

 

I'll be using a spanner, so I guess I need to make sure that I insert the screw only so much that the neo-prene is very slightly compressed.  If you have a tip on doing this by spanner, I'd welcome it!

 

Thank you.

[saveasteading]

Ok. a bigger washer won't really help, in fact it is more difficult to get it flat.

You have a tiny hole to fill. The screw fills most of it so I suggest you just bodge it with silicone and 'glue' the screw into place.

Some into the hole and hand turn the screw in, then slowly with a spanner as there will be little to no resistance.

If you want to glue the washer down to then , no harm.

 

Use good silicone mastic. Get a known brand. clear.. One that says it is for outdoor use, stays flexible for ever, and is UV resistant.

 

You could add a small, angled stripe of silicon just uphill of the screw to divert any water that is running down the crown , away from the screw.