Lean to house pergola, polycarbonate sheets starting to slide down

[OVIP]

Hi All,

I had a lean to house made 3yrs ago, and now 2 of the 9 polycarbonate panels began to slide about 1 inch each, dragging the flashing tape with it…. I assume the panels should have been secured on the joists when installed but they were not. The panels are about 90cm wide and 2.5m long. Our cat has also been climbing on the roof for a year or so by now, so I guess that had an impact as well. Is there a way to push these back and to replace/fix the flashing tape without removing all panels one by one? I was thinking that if I would install some supporting joists between the rafters, 40-50 cm from the wall, maybe I could climb and walk on them and that way could get to the damaged flashing tape and sort it. With the polycarbonate panels I was thinking to remove the gutter and the end stop bars at the end and hammer it up with a mallet. Would it go through the glazing bars? Is this a doable thing or I am lying myself and what I need to do is actually take everything apart..

[Redbeard]

If the flashing remains intact then it seems to me the top (although not where it should be) will not leak. Do you think I am correct in this? If so... cut pieces of 45x45 PSE to fit in each 'bay', fixed to the ledger-plate at the top to prevent 'droop', then make 'tingles' (glorified 'slate straps') to hold the bottom of thhe sheets to stop them falling further. So, 'downstand' down the face of the wall-plate, horizontally across the wall-plate towards the lower end of the poly sheets, then an upstand holding the sheet in place, with a drip-end on it (a little - 15mm? - 'turn-down). Or maybe I haven't read the OP well enough...

 

 

Yes, I hadn't read the OP well enough!! I see the flashing tape is damaged. Scaffold planks across the lot to support you and spread the (otherwise) 'point-loads'. I would suggest do this *after* you have put the restraint straps on the bottom. Then repair the flashing. (Assuming it is 'flashband' perhaps take the opportunity to do in lead - don't forget the patination oil. Unless you feel you have to I don't think there is any need to hammer the sheets back up as you suggest. I think my 'remedials' suggestion sorts that.

Edited 6 hours ago by Nickfromwales

[Gone West]

Polycarbonate panels are usually fitted between aluminium channels, which are screwed to the rafters, and the panels held in place by a sprung plastic strip banged into the aluminium channel. They are usually very tight unless the wrong channel has been used for the thickness of polycarbonate. I would try @Redbeard idea of scaffold boards and remove the flashing and then knock the polycarbonate panels back into position. Fit new flashing and ensure the panels can't move again, possibly with a blob of CT1 between the panel and channel at the top under the flashing.

[OVIP]

2 hours ago, Redbeard said:

If the flashing remains intact then it seems to me the top (although not where it should be) will not leak. Do you think I am correct in this? If so... cut pieces of 45x45 PSE to fit in each 'bay', fixed to the ledger-plate at the top to prevent 'droop', then make 'tingles' (glorified 'slate straps') to hold the bottom of thhe sheets to stop them falling further. So, 'downstand' down the face of the wall-plate, horizontally across the wall-plate towards the lower end of the poly sheets, then an upstand holding the sheet in place, with a drip-end on it (a little - 15mm? - 'turn-down). Or maybe I haven't read the OP well enough...

 

 

Yes, I hadn't read the OP well enough!! I see the flashing tape is damaged. Scaffold planks across the lot to support you and spread the (otherwise) 'point-loads'. I would suggest do this *after* you have put the restraint straps on the bottom. Then repair the flashing. (Assuming it is 'flashband' perhaps take the opportunity to do in lead - don't forget the patination oil. Unless you feel you have to I don't think there is any need to hammer the sheets back up as you suggest. I think my 'remedials' suggestion sorts that.

Hello, yes the flash band is damaged and probably a bit scorched or peeled of on other areas (not only on top of the the 2 poly sheets sliding down)...Regarding using scaffold planks across the roof, I feel that it will not be quite safe as in, walking on them could crack the glazing bars (maybe I am wrong) plus I feel that the scaffold planks could easily slide down the roof with me on top of them...

I was thinking to install timber (100x47) (like the ones in pic 4) between the rafters and about 50cm away from the wall, that should be enough to support my weight I hope and to prevent the ploy sheets from snapping.

Regarding the lead flashing, that would be ideal of course but it will be a hard job to do climbed on the poly sheets without proper support and concerned about snapping the sheets or falling  

 

Edited 6 hours ago by OVIP

[Redbeard]

How about: Take the gutter off, fix notched uprights to the existing uprights, the notches allowing them to protrude up above roof level, and fix a horizontal bearer across. This stops your scaff planks falling off the roof. In fact if you take some timbers from there up the line of the roof to where you want to stand, you can them use those timbers to hold your 'stand-on' timbers. I take your point re installing 'cross-noggins', but are you not still standing on the polycarb even with those underneath, with point-loads of feet, instead of spread loads in my 'model'?

12 minutes ago, OVIP said:

Regarding the lead flashing, that would be ideal of course but it will be a hard job to do climbed on the poly sheets without proper support and concerned about snapping the sheets or falling

See my suggestions above.

 

 

[OVIP]

2 hours ago, Gone West said:

Polycarbonate panels are usually fitted between aluminium channels, which are screwed to the rafters, and the panels held in place by a sprung plastic strip banged into the aluminium channel. They are usually very tight unless the wrong channel has been used for the thickness of polycarbonate. I would try @Redbeard idea of scaffold boards and remove the flashing and then knock the polycarbonate panels back into position. Fit new flashing and ensure the panels can't move again, possibly with a blob of CT1 between the panel and channel at the top under the flashing.

Yes thats how they been installed and the sizes of glazing bars/ poly sheets matched.

What I think happened is that the poly sheets might have been cut a little bit too narrow and there was not a lot of material left to be secured by the glazing bars or the glazing bar plastic top has not been banged properly into place.

[OVIP]

59 minutes ago, Redbeard said:

How about: Take the gutter off, fix notched uprights to the existing uprights, the notches allowing them to protrude up above roof level, and fix a horizontal bearer across. This stops your scaff planks falling off the roof. In fact if you take some timbers from there up the line of the roof to where you want to stand, you can them use those timbers to hold your 'stand-on' timbers. I take your point re installing 'cross-noggins', but are you not still standing on the polycarb even with those underneath, with point-loads of feet, instead of spread loads in my 'model'?

See my suggestions above.

 

 

I am not sure I understand how to use the potential scaffolding planks.

For reference the pergola roof is about 2.5m wide down the slope and about 9m long.

The space between the lower end and the fence is minimal, or less than minimal, about 20cm, just about allowing me to instal and remove the gutter and potentially hammer the poly sheets up with a mallet.The only access to the roof is on the sides unfortunately.

any chance you can sketch a drawing of your support model using the scaffolds? If I am not asking to much?

I am sorry maybe I am thick or something, but I did not understand how it could be done..