Water membrane

[sue25]

Hi,

I have had a green roof put on my shed. There is a water membrane with 30 holes punctured in it at the base of the slope to let water through the drilled holes of a facia board into the guttering.

The plywood roof has been partly protected by bitumen paint. Water is now finding its way back up underneath the membrane on to unprotected plywood.

I am going to put another coat of bitumen and increase the coverage but is there a method of sealing the membrane holes that would allow the water (with a pipe attachment) staight into the guttering. Screwfix and B&Q have been no help.

I am worried the plywood roof will rot! It is one inch thick. Would the bitumen be sufficient if there isn't a fixing?

 

[Alastairreid]

any chance of posting a pic of this set up sue ? having difficulty understanding what has been done and what you wish to achieve.

 

[sue25]

I have put photos on an album on my profile. Is that the way to do it?[/img]

 

[freddiemercurystwin]

Not quite.

Exit holes

• sue25
• 9 Aug 2009
• 1

The holes that I need the water directing through can be seen above the gutter.

Wet patch

• sue25
• 9 Aug 2009
• 1

A bitumen sealant covers 12 inch of the roof down to the holes under the membrane. You can see...

Exit holes internal view

• sue25
• 9 Aug 2009
• 1

These are the puncture holes in the membrane.

 

[Alastairreid]

View media item 13590
View media item 13592
View media item 13591

errm what is that set up? i have never seen anything like it did you do it yourself ?

to what purpose does it serve? is it supposed to be to recycle the rainwater?

sorry sue i'm at a loss with that one! maybe one of the other guys knows of some new invention thats by passed me.

anyway that detailing can never be made watertight or functional imo.

beat me to it freddy.........

 

[Alastairreid]

drop the height of the leading edge of the front fascia board and run the felt straight into the gutter.

 

[sue25]

Green roof almost

• sue25
• 9 Aug 2009
• 1

 

[sue25]

The fleece keeps the soil/substrate in place. It is above the membrane layer. Would some sort of coupling do the job? ie getting water through the membrane and dropping in the gutter.

If I dropped the front what would keep the soil in place?

My brother in law did the job, it was his first attempt at a green roof. It is not finished yet as we have this small issue to sort! PS He is a builder.

 

[freddiemercurystwin]

My brother in law did the job, it was his first attempt at a green roof.

And his last with a bit of luck!

I would try and get the gutter inboard of the fascia with the 'water membrane' dressed directly into it, trying to get the water to find its way through the construction like that is a recipe for disaster as you have found out. It will need some kind of mesh to stop it filling with earth of course but you'll probably need to periodically check it hasn't blocked up. Or get him to try and make up something like this:

 

[joe-90]

One simple idea that should work is to drill out those holes to the size of some easily available plastic pipe (conduit/overflow etc). Lubricate the holes with silicone sealant then insert the pipe (must be tight fit) from the roof down into the gutter. That should be a watertight fit if you do it correctly.

 

[sue25]

[I would try and get the gutter inboard of the fascia with the 'water membrane' dressed directly into it, ][/quote]

I think this is the easiest remedy trying to sort the mess we are in, combined with drilling tight holes for the pipes through the facia.

The main question is if I cut the membrane so it is tight to the facia, can I stick it down with anything to try and stop any water going back up underneath itself? Any recommendations?

Many thanks for your help.

 

[freddiemercurystwin]

I'm not quite sure what you mean tbh but anyway if the gutter is behind the fascia sat on top of the existing deck, out of sight so to speak, with the membrane dressed into it, (you would need a fillet piece of timber to stop the membrane draping) then the water can flow directly into the gutter and it will never get under the membrane in the first place. As mentioned you will probably need to move the fascia further out so that the downpipe can run vertically through the soffit below as the soffit at the moment looks too narrow. Otherwise I don't see how the downpipe can get out, unless you had one end of the gutter poking out at one end which would look a bit of a bodge. (previous colossal bodges forgiven! )

Edit: having just re-read your last post, to sum up, trying to sort this by drilling holes in bits of wood for drainage is a right bodge and you'll end up with the same problems you have now. Fix the UPVC gutter behind the fascia, dress the membrane into it and drain it with a downpipe through the soffit.

Untitled

• freddiemercurystwin
• 3 Sep 2009
• 1

 

[Deluks]

Exit holes??

My foot would be finding it's way into the exit hole of anyone who did this to my roof!

 

[justlead1]

Hi freddy, have a method that may help this post. But need advise on, making and posting sketch. Can you advise?

 

[freddiemercurystwin]

Hi freddy, have a method that may help this post. But need advise on, making and posting sketch. Can you advise?

You mean advise on doing a drawing? I'm not sure I get your drift! If thats what you mean, you can't beat a hand drawn sketch and a photo of it.