How to fit step flashings
- Step flashings – What they are and when you need them.
- How and when to install step flashings – And step and cover flashings.
- How to fit lead soakers – The unsung and unseen waterproofing heros.
- Abutment soakers – Why you need them, when to use them and how to fit.
There’s nothing particularly difficult about making and fitting step flashings once you know the basics. Unfortunately a lot of builders, and I’m afraid to say some roofers get the basics wrong, and it often results in leaking roofs sooner or later. In this article I’m going to show you not only how to make step flashings, but what type of step flashing to fit on what type of roof covering, when and why.
And what’s more when done correctly they will last a lifetime, very simple and no leaks!
What is a step flashing
A step flashing is a roof flashing that allows a roof to abut brickwork for instance when a lower height roof runs into a wall, a roof meets a chimney, or a conservatory roof meets the wall of a house. The ‘step’ referred to is the pattern created in the lead by a series of cuts that allows the lead to penetrate into the courses between the bricks that resembles the steps of a staircase. The reason for going to the trouble of creating the steps is so the bricks can remain un-cut and therefore undamaged, as well as it being aesthetically pleasing.
Step flashings – There are two distinct types of step flashing on a roof and getting them wrong can create leaks. ‘step and cover’ flashings are mostly used for profiled tiles. However ‘step flashings’ are used for slates and double overlapping flat profile tiles with accompanying lead soakers, like the plain tiles pictured.
Which step flashing – Step & cover flashings are nearly always used on profiled interlocking tiles (right), an abutment soaker should be used with flat profile single overlap concrete tiles as see in the picture (left). Step flashings with soakers are used for double overlapping plain tiles or slates seen (middle).
Step flashing fitting guide
Step flashings are quite easy to make once you understand the basics, especially If you’ve already seen my video and article on how to make standard apron flashings, otherwise known as cover flashings. Please check it out if you haven’t as the video contains lots of tips on fixings, chase depth and how to point up a flashing correctly so this isn’t repeated later in the videos on this page. This is vital knowledge you can adapt to the flashings talked about here.
- How to make apron flashings – Also called cover flashings, check out this page at some point there’s lots of professional tips that will help.
- How to make step and cover flashings – Used on profiled tiles and some flat single overlap tiles, but with limitations i.e. an abutment soaker.
- How to make step flashings – Used for all types of slate roof and small plain tiles like 6″ double overlapping tiles (150mm).
Step and cover flashings
Step and Cover – This video on how to install step cover flashing shows you the basics of flashing into a brickwork wall and supplying a waterproof cover, all in one flashing.
How to point brickwork – This is a beginners guide to pointing up. Great for brickwork, chimneys or roof details like flashings.
Step and cover flashings are possibly the easiest to fit because they incorporate the ‘step’ and the ‘cover’ aspect of a flashing, the cover simply folds over the highest point of a roof tile and is then dressed into the lowest. This makes the roof waterproof in a very simple fashion because any water rolling down the surface of the flashing is trapped in the lowest part of the roof tile all the way to the bottom of the roof and into the gutter.
Step & cover – This type of flashing can be used on any roof covering that has a profile to it. It should not be used on small flat double overlapping plain tiles or slates either natural or man made however.
Step flashings to a conservatory – Step and cover is also fitted where a conservatory roof is joined to the house. Here the lead is flashed over the upstand on the glazing bar closest to the house and onto the conservatory roof.
Step and cover flashing mistakes
Step and cover flashing is not usually suitable for small flat profile non-interlocking tiles because the high and low peaks needed to render the roof waterproof do not exist. If you have small double lap plain tiles as pictured below right you will require lead soakers and standard step flashings to cover them, as seen in the videos and article further down.
When step cover flashing is wrong – These flashings do not belong on these slates or tiles, these are both flat and double overlap, meaning standard step flashings and lead soakers should be fitted.
If you don’t understand what double overlap is, this is explained on my how to slate a roof page.
How to install Step flashing
Here we’re talking about standard step flashing, this is used, or should be used on roof slates both man made and natural slate, as well as small flat plain tiles with double lap. It is a very simple flashing to make and very similar to the step & cover flashing mentioned above, but without the ‘cover’ aspect. This time though because flat tiles or slates have no profile to cover, other than being flat, they require lead soakers to make the roof waterproof. This seems to outwit many builders and sadly some roofer’s but it really is very simple and fast once you understand the basics.
Step flashing video – This video on how to fit step flashing shows the correct method of fitting plain step flashing to a wall or chimney. The example here is on the side of a chimney stack with slates, but the same technique is used for plain tiles or any brickwork wall.
Combine the above video with the video below and you will be able to correctly flash slates or plain tiles to the side of a chimney stack or to any abutting wall.
How to make and install lead soakers
Lead soakers are just small sections of lead bent and cut into an ‘L’ shape, usually out of code 3 lead often referred to as flashing lead. Starting at the bottom of the roof on the very first course of slates or tiles called the ‘eaves row’ or ‘starter course’, it’s just a simple matter of fitting one soaker per row of slate or tile and then with every additional row thereafter. This way if any water gets between the tile or slate above, the lead soaker underneath catches the water and directs it on top of the tile below, and so on and so forth.
How to fit lead soakers – Easy to make and simple to fit, by far the easiest method for slates or double lap roof tiles. This video on how to fit lead soakers shows you how easy it is for tiles or slates.
Use this video in conjunction with the plain step flashing video above for the complete guide on step flashings and soakers.
Unfortunately lots of roofers and builders through either ignorance, laziness or competitive price reasons, particularly on new housing estates, use step cover flashings on slates or tiles where they should not. Ironically I find the membrane or undersarking normally fails after the NHBC warranty is just out of date. Although the step & cover flashing may hide the joint between the roof and wall, a factor called ‘ angle of creep ‘ allows water to seep sideways under the flashing and into the roof space.
Missing abutment soaker – This short video deals with why these soakers are often missing, it’s not always the roofers fault believe it or not.
How to Install an abutment soaker – This video shows how to install an GRP abutment soaker, sometimes called an abutment gutter, secret gutter, or dry fix soaker.
Abutment soaker size – There are a few makes of GRP soaker on the market with very subtle differences, this is pretty much a standard size and shape (Harcon I believe). Other examples, often with sizes can be found on websites like the roofing superstore.
Angle of creep on a lead flashing is when water gets underneath the overlap part of the flashing that covers the face of the tiles, when the water gets under here it will either be blown in with an unfavourable wind, or simply creep sideways of its own accord. This gets worse and more pronounced the longer the run of flashing is and then relies on the undersarking not to give way, which it normally does at some stage either sooner or later.
Water creep under roof flashings – Here the large single overlapping Marley modern roof tiles are suffering from angle of creep. The longer the length of flashing the more prone to water creep it becomes, so additional waterproofing measures are required.
Leaking lead flashing – This is the lead at the bottom of the roof above lifted for a quick inspection. Even in moderate rain this was leaking thanks to 11 years of water ingress ruining the undersarking. Once again no abutment gutters fitted.
Step cover flashing isn’t the wrong type of flashing on large flat single overlap interlocking tiles like the Marley Modern or Redland Stonewold … BUT additional waterproofing should be taken like the fitting of secret abutment gutters otherwise known as an abutment soaker, the trouble is this takes a little more time and effort so it seems to get conveniently ignored. Often.
Marley modern or Redland stonewold – The step cover flashing is correct on flat single overlap roof tiles like these, as well as other types of flat single overlap roof coverings, but secret abutment gutters should be fitted.
Abutment secret gutter – Here I’m retro fitting an abutment gutter to step cover flashings to fix another leak on new housing. These days abutment soakers are pre-made from fibreglass, but they can be made in the traditional manner from sections of overlapping lead. Again these are single lap interlocking roof tiles.
Sometimes in the place of a secret gutter a bead of silicone or mastic is pumped underneath the lead flashing and onto the surface of the tiles or slates in an attempt to create a waterproof upstand seal. Although successful on some occasions and better than nothing this is still in the realms of bodging, and I would not consider it personally.