Filling screw holes in metal roof

[groeneaj]

I’m removing the old solar pool heating off my roof and need to fill approximately 20 screw holes.

I’m thinking of filling the holes with sikaflex, then inserting a larger diameter screw. The problem is, some of the holes have no timber roof beams underneath so not sure if it’ll seal properly. Does anyone have any experience in this and can point me in the right direction?

Cheers,
Andy

[RobbieB]

If there's timber underneath, roofing screw with a seal washer. Screws will come out if there is nothing under the sheet, which will lift the sealant eventually. Can you put rivets in those holes?

[Beardy]

Put in a large rivet and then a dab of roof and gutter silicone over it

[Chris Parks]

Blind rivets are waterproof.

[Beardy]

Blind rivets are waterproof.

But what seals the mandrel of the rivet to the roofing sheet also roofing rivets sold are not the blind type but are open

[rjtwin501]

Cut off some of the stem of a roofing nail, put some suitable sealant under the head then push the pin through the hole and firm down onto the roof.
The sealant trapped under the head will hold it in place and last for years. Got some I did at my place 40+ years ago still going strong.
The old timers often used gal clouts on a gal iron roof and before silicone they were soldered on.
I have seen the soldered clouts used an a water tank that someone had shot up with a 22.
Cheers
John T

[volvo]

just a couple of ideas. I assume the holes are about 6 mm diam. I have seen old water tanks repaired with curved washers a nut and bolt and bitumen [ replace with roof silicone] curved washers from zinc strip. Or turn some treated pine cylinders to fit the curve and cut lengthwise, and use these as a curved washer with silicone. This is how I would attack your issue. volvo

[Chris Parks]

But what seals the mandrel of the rivet to the roofing sheet also roofing rivets sold are not the blind type but are open

Silicone breaks after a while. Given the space in the roof and accessibility to the holes I would cut pre drill some patches, glue them to the underneath of the hole and put another patch on top, rivet or screw together.

[Simplicity]

Can you access the underside of the iron,
If so,you could place short bits of timber underneath and have someone drive roofing screws in from the top side.
Not pretty I know but easy!!

Cheers Matt,

[Beardy]

Silicone breaks after a while. Given the space in the roof and accessibility to the holes I would cut pre drill some patches, glue them to the underneath of the hole and put another patch on top, rivet or screw together.

Silicone is the recommended product for rainwater products and roofing, all your flashings and gutters including box gutters are sealed with silicone and rivets as per manufacturers instructions.
Although I recently was on a job that had SS box gutters and flashings and they were all soldered with expansion joints built in. It cost a fortune though, the roof cost more than most people spend on a house.

[crowie]

Andy, I’ve used in the past polyurethane sealant with a large polycarbonate weatherproof deal over the top of the hole together.
The seal is similar to this one
https://www.bunnings.com.au/zenith-2...-pack_p2409517
cheers Peter

[damian]

Been doing my roof these last few weeks.

Get 14 g tek screws, no washers. Get UV proof sealant goo. Put goo on screw or roof, drive tek screw gently. The 14g thread is big enough to bite a 12g hole. Quick and it'll be fine.

Be aware if it's a steel roof you have to be careful of mix and matching gal/colorbond. Gal screws in colorbond for example promote rot. Lysaght etc have online info sheets on that. Likewise use rivets of the wrong material and your roof will rust out in no time.

Also don't stress too much. If teh holes are on top of ridges little or no water will get through, even if it does if your roof has a decent pitch it'll just run down the inside. Even if it drips it'll boil off next sunny day.

[groeneaj]

Thanks for replies. I’ll look into all the replies and see what I come up with, then post my results. Cheers