3 Things To Consider When Putting A Roof On Your Extension

As I’m sure the majority of you will know, we completed an extension/conservatory makeover on the back of our house this Summer, which has made an incredible change to the whole dynamics of the downstairs.

Building on to your house gives additional space depending on your needs. From smaller extensions such as utility rooms, porches or even downstairs WC’s to larger extensions to create large additional rooms or to increase current floor space such as making a kitchen bigger.
We were lucky enough that my mum & stepdad are super handy & built their own house (which I’ll be blogging about soon!) so did most of the work ourselves to keep down costs.

One of the things that came up was what type of roof we were going to put on the existing conservatory to turn it from an unusable leaking cold/hot room to more of an extension.

Here are my top 3 tips to consider which options right for your extension project –

1. Cost – the cost of your chosen material will no doubt eat up a huge proportion of your budget. We wanted ours to be as cheap as possible, but also took into account how functional it would be as we didn’t want to replace an already unusable space with something that would be equally as awful. The cheapest option is felting which is basically the same as the top of most shed roofs. This was something that I felt strongly against though due to the maintenance & longevity aspect of it. I didn’t want something that would leak in x amount of years (exactly what I was trying to move away from with the conservatory) & would have to be redone. The most expensive options are slate or clay tiles.

Insulating helps stop heat escaping.

2. Functional – how practical is the roof you’re putting on? Think about durability, resistance, suitability & so on. You’ll want something that is long lasting, resilient, weather proof & light weight.

2. Appearance – obviously when you’re spending thousands on something, you want it to look nice as well as being functional (see point number 3) however, it’s the same with most things in that the most expensive options, such as slate or clay tiles, generally look the best. For many though, a roof is a roof & unless you can see it constantly then it shouldn’t matter all too much as you’ll be below it rather than above it staring most of the time. 

To finish off the look & blend it in with the garden we added Cedral weatherboard cladding.


After calculations from a surveyor, we realised that we didn’t have enough gradient for a pitched roof, unless we had a considerably lower ceiling which I didn’t want to do, especially because of how high the ceilings are in the rest of the house. This was because of the windows directly above the extension (our bedroom, en-suite & soon to be office). This meant that most options were out of the question.

Due to budget, we also didn’t want to have to go crazy on the additional support. With the surveyors calculations, we realised that if we used a lighter roof material we would be able to use timber instead of steal which saved us a great deal of money.

Our two options were felting, which like a shed would require constant maintenance & not last that long but be the cheapest option OR rubberising which is what we went for in the end.

This is where a special rubber is placed on top of the roof & carries a 35 year guarantee. It took 2 men about 3 days to lay this large space & around the 2 roof lanterns.


This will be one of the most important factors to consider when planning your building work so it’s worth taking your time on this decision & taking into consideration all materials & options depending on the above 3 points. You’ll find experts on sites such as mybuilder.com who will no doubt be able to advice on the best option too.


Have you put an extension on your house? I’d love to hear your tips.




  1. January 1, 2017 / 11:09 am

    We are hoping to get a double storey extension build on the side of our 2 bed house this year. We are completely new to the whole thing so your blog was really helpful! x

  2. January 1, 2017 / 5:06 pm

    We are doing exactly the same as 'evelynhart14' – how bizarre!

    Moving into our new home hopefully this month and looking at getting an architect over to draw up plans of a 2 storey side extension adding two further bedrooms and then a single storey extension out the back for more living space (a bit like what you've done Charlotte). Exciting times, this blog has been very useful thank you!

  3. January 1, 2017 / 7:03 pm

    Hi Evelyn, it'll make such a difference…this is by far the best thing we've done x

  4. January 1, 2017 / 7:04 pm

    You definitely won't regret it, especially with a 2 storey extension…if you've got to dig the foundations etc then you might as well go up as well as out. Good luck with the project! x

  5. October 2, 2021 / 12:12 pm

    Your ideas are amazing. I am so pleased to found this post. Thanks and keep sharing.