When your flat-roofed extensions were built, they probably seemed an appealing proposition. Now, you’re likely dealing with leaks, extreme heat, and an all-around uncomfortable space during the majority of the year. Switching to a different roof system can convert the room from hardly usable to an area you will want to spend time in.
A classic case is the kitchen or dining room extension with an old flat roof that has had better years. Water collects after serious rain and the room is an ice box in winter with the heating full blast. Afternoon summer heat is unbearable. You’ve gone to the trouble of patching the roof and the problem just keeps re-occurring.
What Conversion Actually Means
When most people talk about converting a flat roof, they mean changing from the old traditional felt type or asphalt system to a modern single ply membrane system, or in some cases all the way to a pitched roof. Each of these options can solve certain issues, but they can all add to costs and complications.
Choosing a higher-grade single-ply membrane for the flat roof will keep the flat roof profile, while also giving appropriate waterproofing and insulation. This is the least disruptive option. It will only be a few days of work, minimal impacts on the inside of the room, and will be reasonably priced. It will cost anywhere from £60 to £100 per square metre for a decent job, with the cost covering an upgrade to the insulation as well.
Changing to a pitched roof will be more work. It will completely change the character of the space, and you will need to consider obtaining planning permission, as well as building regulations, and how it will aesthetically fit with the rest of your house. This will take longer and cost more, but will provide you with a room that is fully insulated and functions like the rest of your home.
Regulatory Burdens of Conversion that are Universally Dreaded
Both conversions are subject to building regulations. No matter which option you choose, your roof must comply with the most up-to-date insulation standards. Building control inspectors will ensure regulations have been followed.
Gaining planning permissions often poses a headache. Planning permission for pitch roofs especially needs consideration with respect to height increases, with the exception of pitched roofs in a conservation area. Flat to flat conversions, however, usually do not need planning permission. However, in all cases it is best to check with the local authority first. Doing work only to have to undo it for not obtaining proper permission leads to unnecessary costs.
It is key to have a proper assessment of the structure. This is important to ascertain if the existing walls were built to hold the required additional weight of the pitched roof. Strength reinforcing structure to support the pitched roofs extension will be an additional cost. This is another reason instructions from the engineer should be prioritized.
Enduring the Disruptions
Disruptions will happen. Replacing membranes will render the extension unusable for several days. Converting to pitched roofs will have an even bigger impact on the house for a longer time as it will not happen until the weather is dry and the time is sufficient. This means the time to complete the conversion is weather dependent.
Roofing work is severely weather dependent with the exception of the cold and rainy day. Under colder conditions the work will take longer as there will be fewer working days. While the contractor will be busy in the spring and autumn. During these periods the contractor will be less reactive to your needs as they will be busy, so it is best to have the work scheduled as soon as possible. Otherwise there may be long waits in the in the spring and early autumn months.
The mess factor differs for each type of work done. Membrane replacement usually happens on top of the roof, so the work is done rather clean. However, pitched roof conversions can be very disruptive, especially since they tend to involve structural work that affect the ceilings below. So, expect some dust and noise, as well as your extension being fully out of use.
What about the final results of the conversion?
Your temperature issues could very well be solved with proper insulation and ventilation, so your energy bills should drop as well. Most people are able to see the conversion “pay for itself” in energy costs in 8-12 years. The room finally being usable means the improvement is likely magnitudes better than that.
The aesthetics of your extension are improved, which is especially good for the overall value of your property. The presentation of your property is impacted in either direction, so the improvement may help when you finally decide to sell the property, especially when you choose a nice patch roof to go with a modern membrane.
Issues caused by flat roof conversions getting worse over time, so a flat roof conversion gives a permanent solution to an ongoing problem. Take time to figure what needs to come out of the space, consider getting some proper estimating quotes from contractors, and set a budget to do it only once, even if it means spending more money.