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How to fit lead flashing on a conservatory

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When you install a brand new DIY conservatory, the last thing you want is rainwater trickling through the roof, soaking everything inside.

That’s where conservatory lead flashing comes in handy – and you’re about to find out the most safe and straightforward way to install it.

Keeping your conservatory protected from the elements is the best way to ensure that it’s a fantastic place for you and the family to spend time for years to come.


What is lead flashing?

Flashing is essentially the formation of weather resistant material placed against a structural joint to prevent the passage of exterior water between the seams.

It has a useful part to play around many sections of a building – whether that’s chimneys, ventilation, walls, windows and door frames. Besides protecting these areas from leakages, it also acts as a deterrent to indoor mould issues.

Although flashing is commonly made from lead, there are a number of other impervious materials that can be used as flashing – including zinc, stainless steel, aluminium and copper.

roll of lead flashing


Where can I buy lead flashing?

So, how much does lead flashing cost and where is it sold?

You don’t need to be a builder or any other type of tradesperson to access lead flashing. In fact, you can purchase lead flashing for a reasonable price from various DIY retailers.

Typically, they’re sold in rolls ranging between 3-10 metres long. Therefore, it’s a good idea to get the measuring tape out and find out exactly how much you need before heading out to the shops. You may find that one roll isn’t enough.

You’ll also want to check the width and density of the flashing (in millimetres). The thicker the material, the more robust it’s likely to be and the more protection it’s likely to offer. In areas which are flat, or more prone to collecting rain water – you’ll probably need the thickest option available.

While you’re out and about, you’ll probably want to pick up some sealant as well. You can get super-strong adhesive for bonding lead sheets right where you need them.


Conservatory lead flashing

Now that you’re familiar with the basics of lead flashing usage – you’re probably wondering where you’d use it on a conservatory?

When you think of the structure of a conservatory, it’s easy to see why flashing is important from a weatherproofing perspective.

A conservatory is basically an extension on to the exterior wall of your house. Between the wall and the conservatory roof, the seams need to be covered to prevent the passage of water.

Obviously, the roof on a conservatory is different to the roof on a house, but the principle is basically the same. It’s a case of fitting the conservatory flashing to neatly cover the area where the edge of the roof meets the exterior wall.

conservatory lead flashing

Fitting lead flashing on a conservatory roof

The first thing to bear in mind is that you’ll need the relevant tools and materials to complete the job. – One that’s vitally important is a safe and sturdy ladder.

No matter how light you think you are, conservatory roof panels aren’t constructed to support the weight of a person. Place a flat plastic surface across the roof beams so you can lean across to apply the flashing in a safe and sensible manner.

How to install lead flashing

Step 1.
Remove the line of mortar between the external brickwork of your house to accommodate the flashing. For lean-to or flat roof conservatories (i.e. a roof that slopes outwards), a singular long line of mortar between two layers of bricks needs to be either chiseled or grinded out to a depth of around 25mm. Make sure this line isn’t too high above the roofing bars, and that there’s enough room to fit the lead flashing sheet sufficiently.

Step 2.
Roll the sheet across the top of the roof frame – sliding the top of the flashing into the mortar as you do so. If you’re happy with how the flashing line looks, refill the lines of mortar to set the top of the flashing into the brickwork securely and seal it down across the edge of the roof frame neatly (it’s best to do this on a warm dry day, so everything can set properly).

If you’re fitting lead flashing on a conservatory roof that slopes parallel alongside the exterior wall of your house (as opposed to sloping outwards)the best thing to do is apply the stepped flashing method. It’s more time-consuming, but this approach is the only way to ensure that your roof is fully protected.

If your roof is sloping downwards against the exterior wall,you won’t be able to isolate one line of mortar between the two layers of bricks. Instead you’ll need to chip the mortar out in a stepped fashion as you work your way down where the edge of the roof frame meets the wall on either side.

Then, you’ll need to cut your lead flashing sheet into smaller ‘steps’ that follow the edge of the roof frame as it slopes down. Follow the same process above to fix the flashing – just refill the mortar accordingly and apply the sealant.


Professional conservatory leak repair advice

If you’re wondering what to do if your conservatory is leaking, despite having flashing in place – we’re on hand to help with any concerns you have.

You can get in touch with the ConservatoryLand team directly and get the necessary repair advice. Your concerns might be easily remedied by a simple solution – all you need to do is get in touch.

Also, bear in mind that if you’ve purchased a DIY conservatory with us – any leaks caused by faulty materials are covered under the ConservatoryLand guarantee.

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