How to re-attach box gutter to rendered wall?

[tigerzen]

The box gutter has detached itself from the rendered wall. I tried a similar screw which was a little larger than the original but it didn't hold. It seems impossible to find the stud behind the render so I'll need to drill into render and blueboard(?). Are there special screws that will work in this instance, is there another way to attach this gutter?

 

[Noyade]

Afternoon @tigerzen 

I'm not expecting you to own an orthopaedic screw depth gauge, seen below, but you can replicate something similar with a length of wire and a sharp small bend at the end.

Remove the Tek screw seen in your photo.

Start probing.

See if you can find 'wood' inside. Anything that could accommodate a screw and also noting the direction and length required.

If just an empty cavity - rest the bent end on the inner surface of the wall - mark the wire.

Depending on the length - I'd then start looking at hollow wall anchor hardware.

If any of that makes sense.

Cheers.

[R4addZ]

Hi again @tigerzen 

I decided to go looking for something that could take more weight. Again I would replace the supplied screws with galvanised or stainless but with these, according to the weight they supposedly can take, I would expect the blueboard to give way before the fixings. Bunnings special order team may be able to get them in for you.

https://shakespearesolutions.com.au/products-page/wall-fixings/geefix-cavity-wall-fixings/?srsltid=A...

A bit more work to fit but a massive increase in weight handling!

[Nailbag]

Hi @tigerzen 

A stud finder definitely wont work through render unfortunately. And I suspect its possible that behind the render is actually foam board not anything solid such fibre cement blue board. The original screws have given way because they were only screwed carefully just into the render itself being less than 100mm thick.

You can test this by making a small 4mm hole just through the render itself. Then see if you can push through an open ended coat hanger wire, If you can then its foam board, which traditional fasteners wont be effective.

You might need to fix a metal plate to the back of the header (box gutter) with screws or rivets. Then apply a Sika-flex adhesive to the back of the plate and then put a prop hard up against the head over night to all the adhesive to dry.

Nailbag

[tigerzen]

Thanks Noyade and R4addZ for your thoughts, I appreciate your input. I did probe around the holes and I didn't detect anything solid. Looks like it will have to be some sort of cavity fittings, from what I can tell every fixing has used these self-tappers so could be a few to replace but I'll wait until they're a problem before I change them, atm it's just the box gutter.

[tigerzen]

Nailbag, you're right, it's foamboard, not fibre-cement making it worse than what I thought. I contacted a plumber today who wasn't sure what attaching method to use, he said he'd need to research it further.

[EricL]

Hello @tigerzen 

I propose following @Nailbag's suggestion as there are no studs or solid fixings behind the foam board.   

Eric

[tigerzen]

Thought I'd give an update on this. We engaged a plumber who promptly gave us the bill and said it was fixed. I went up to have a look and it's in exactly the same shape it was before ie not connected and with some silicon patches which were used to try and attach the gutter to the rendered wall. Now it's worse as there are repeated attempts at screwing fasteners into the rendered wall which have now left some bigger holes in the wall. I have no idea how to plug these holes (builder's bog perhaps?). I have since discovered that the exterior walls are polystyrene panels with a few layers of render so not sure how to fill the gaps. Back to square one, finding a prop to hold the gutter to the wall seems difficult as it's high up off the ground.

[MitchellMc]

Hi @tigerzen,

I'd be inclined to fill all the holes with exterior silicone to prevent water ingress, or you could use mortar and paint over it. 

For the fixings, as Jacob mentioned, I'd go for an expanding toggle. However, if they are long enough for the thickness of your sheets, go with Ramset 3/16" x 100mm Round Head Spring Toggles as the wings will capture the back of the sheets. However, if you have 100mm thick sheets, these likely would be long enough. The other option is to potentially try Wallmates. When fixing lightweight objects to foam board, a similar style of screwed fixing is used.

Mitchell

[tigerzen]

Thanks Mitchell for the advice. After poking around in the polystyrene walls it feels quite thick, do you think the toggle bolt would still work? Also I thought Builder's bog would be a better filler as it can be screwed into therefore creating a place to hang the gutter to.

[EricL]

Hello @tigerzen 

Are you referring to the Ramset Super Wallmate Toggle Anchor? Did you have another toggle in mind? If it is the Super Wallmate, it's important that there is enough space for the toggle itself to swing loose in order to operate properly.

If you need further assistance, please let us know.

Eric