How to fix water sitting on flat roof?

[mills28]

Water sits on top of my colorbond pergola only on 1 side. How do i fix this on a budget. It seems the roof doesnt slope correctly. Is there any sprays etc i can use to repel water from sitting in these spots

 

[JacobZ]

Hi @mills28,

Welcome to the Bunnings Workshop community and thank you for your question.

Unfortunately, there is no quick fix, such as a spray that is going to fix this issue.

The issue is there because there is simply not enough slope on the roof to make the water run off. The only solution is to increase the slope of the roof.

This could be done in two ways: either increasing the height of the house side or reducing the height on the gutter side of the pergola. In your case, as the roof seems to be touching the underside of the gutters, then the gutter side of the pergola would need to be lowered.

Is it possible to get some photos of the underside of the pergola? This might help us better understand what you are working with and offer a solution.

Unfortunately, I don't see the solution being particularly simple.

Allow me to tag @Dave-1, @AlanM52 and @Nailbag for their thoughts.

Jacob

[Dave-1]

Good morning @mills28 

Welcome to the Bunnings Community pages You have a nice question to start off with, maybe not an easy fix but hopefully you can find something helpful within these pages. I do not know of a spray that would repel water to that degree. Fixing the dip is what i would suggest to do.

Looking at that photo (A few more would be nice ) where the water is resting seems also to be slightly bent? Not sure if its the photo or actual dipping. 

You could have a look underneath and see what type of structure is supporting that area, maybe add a new piece of timber to smooth out that dip. It will probarlly be involved installing a new piece of timber but a few photos and we can hopefully step through ideas.

An overall shot of the underside,

The area in question from the underside, with the closest supports in the pic.

The attachment to the house eaves.

You can get an estimated/calculated fall of the roof by using your level and a tape measure.

If you have a 1m level, you can place it on top or below but on the metal sheet, then move it up or down until the bubble is centered in the middle of the level. measure the distance of the end of the level from the metal. Maybe 1cm, That would mean you have a roof fall of 1cm for every meter, if you roof is 4m long then a 4cm drop. There are a bunch more equations you can look up but really you just want to see what your roof fall is.

Dave

[AlanM52]

Hi @mills28,

Hmm... the water is pooling around those two roofing screws and maybe a third one on the left.

@JacobZ and @Dave-1 have asked for some more photos so please also include photos from below of that area at different angles.

A couple of windows packers might encourage the water to keep flowing past that area - maybe?

Cheers

[Nailbag]

Hi @mills28 

As @JacobZ mentioned, it's caused by not enough fall in the roofline in that area. However If the only issue is that there is water pooling just in that small area and no other flow back doing heavy rain back towards the house causing leaking, then I wouldn't be too concerned as it will simply evaporate.

Having said that and to expand on @AlanM52 thought, you could pack the sheets between the top of the joists and the fastening clips. This would require the Klip Lok sheets to be lifted/disconnected to the fastening clips. Then the clips removed, packed and refastened.

Nailbag