Over time, single-skinned timber buildings can develop rot due to moisture ingress. This usually occurs in the bottom boards of a shed or summerhouse, where the building is most exposed to rain and ground moisture.

While it can be frustrating to spot rot on your building, replacing weatherboard is usually a straightforward repair. With the right approach, your shed or summerhouse can be back in full working order in no time.

In this blog post, I’ll explain a few simple methods for replacing rotten weatherboard, as well as where you can source replacement boards for your G&M Shed or summerhouse.

How do I decide which boards to replace?

Start by checking the cladding and marking out which boards are rotten or damaged. 

It’s also worth deciding if you want to only replace the visibly rotten boards, or if you want to replace a larger section of boards to be on the safe side. 

Site Manager Calum usually recommends replacing two boards above the rotten area as well, because rot can be present in these boards, but it might not be visible. 

Can I slide the board out?

Yes, this is one way to remove rotten weatherboard.

Punch the nails into the frame.

Using a nail punch, you can punch the nails right through the weatherboard and into the frame behind it. 

This releases the boards so that you can slide them out. 

Remove the corner strip.

Next, remove the external corner strip on your Shed. 

Once the corner strip is off, you’ll be able to slide the weatherboard out of place. 

Remove the rotten boards.

If the board slides freely you can simply pull it out from the side. 

If it’s not moving easily you can attach a small block of wood to the hollow of the weatherboard and gently tap this with a hammer until the board is knocked along and slides out. 

Can I cut the board out?

Another option to remove rotten weatherboard is to cut the boards out. 

Using a circular saw, make a horizontal cut about 20mm down from the tongue, and 20mm up from the groove, making sure to avoid the nails. 

Once cut all the way along the board, you can knock out the cut section with a hammer from the inside. Then you’ll easily be able to pop out the tongue and groove. 

Here’s a short video of Calum explaining how weatherboard can be replaced:

How do I fit the new weatherboard?

Once the rotten boards are removed you can easily slide the new weatherboard into place.

You do need to make sure you have enough clearance to slide the new board in though. 

For example, you’ll need 10ft of room to slide in a 10ft board. 

Once the board is in place, nail it back into the frame and reattach the corner strip. 

What if I don’t have enough clearance?

If you don’t have enough clearance to slide the full board in from the side, you have a few options: 

One option is to replace all the boards from the bottom up to the rotten board that you’re removing. This allows you to slot the new boards in vertically rather than from the side, working from the top of the removed section downwards.

This works because the bottom board doesn’t need to slot its groove over another board, making it easier to fit the final board into place.

Another option, if the rotten board is higher up or in the middle of the panel, is to remove five boards or more together. When several boards are connected, they have enough flexibility to bend slightly into a curve.

This lets you slot the group of boards into position and then push them back into place, even if you don’t have the full side clearance.

Where can I get replacement weatherboard? 

The best place to get replacement weatherboard is from Direct Line Timber in Dundee – they can provide you with the same profile of weatherboard that we use in our Sheds today. 

We recommend phoning ahead with the length and number of boards that you need (the width will be 19mm). If your building is particularly old you might need to bring in an offcut so that Direct Line Timber can match it for you. 

How do I replace rotten weatherboard on a Shed or summerhouse?

Now you know how to replace rotten weatherboard on your building, your Shed or summerhouse is on its way to being as good as new. 

Taking the time to repair rotten or damaged boards early can help protect the rest of your building, keeping it performing its best and lasting for years to come. 

If you’re still unsure how to replace rotten weatherboard on your Gillies & Mackay Shed or summerhouse, you can email us at info@gilliesandmackay.com and we’ll be happy to help you.