Lean To Shed

by John Andrews

I have a predicament and hope that your vast shed knowledge can help.

For years now my shed has been leaking like a collander all the wood is rotten and there are slugs on the walls, and I have had enough.

I have just got an uncle to donate some wood he had lying around and have decided that this is the year that I replace the roof.

BUT...the shed I have is not a shed.

Confused I hear you say, the shed is built on the end of my house with the kitchen window right above the flat useless roof so a nice apex is out of the question says the wife.

Is there any way that you can put guttering on the wall under the window and flash it in or does that only work if you have four sides to a shed?????????

Please help. You probably will need more info unless youve come across it before? thanks very much.

Kind Regards

John Andrews

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Mar 10, 2009
Thanks for your help
by: Anonymous

Thanks John,

I will send you a picture of my dilemma when I have a moment. Yes I am on a hill and my garden is 7 to 10 feet below the floor level in my house. We have to go down steps to get to the garden.

Will update you asap thanks.


Mar 09, 2009
Help with flashing detail to brick wall
by: John - Admin

Hi John,

The way I understand it you have a flat roofed lean-to shed up against the rear wall of your house. You want to replace it with a similar (but better constructed) building.

The bit I am not quite clear on is how the kitchen window looks out above the shed roof (possibly your house is on a slope?)

Anyway if this is all being re-done from scratch you need to make sure that the flat roof is not flat! It should have a minimum slope of 1 in 60 away from the house and the water collected in a gutter at the lower edge of the roof away from the house.

Up against the house, which I am assuming is masonry, you will need to use a lead flashing which will come at least 150 mm up above the level of the roof.

The flashing has two functions:

• Firstly, it weatherproofs the junction between the house and the shed from driven rain flowing down the face of the house.

• Secondly, it protects the masonry from splashes of rainwater bouncing up from the shed roof. If the masonry gets wet and with freeze/thaw action it will deteriorate over-time.

If you would like to send me a picture of the shed location, I will send you a typical detail of how to flash a flat roof into a brick structure.

I hope this helps.



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