Garages do require regular maintenance to keep them free from leaks and water damage. According to the Roofing Association, the average life expectancy of standard flat garage roofs is around 10 to 15 years. The use of modern materials such as fibreglass can extend this to 20 years or longer.
After then, materials will likely begin to wear and tear, resulting in holes, leaks and other forms of damage.
The worst result of poor garage roof maintenance is damage to the frame or foundations. Most garages use a timber frame which is vulnerable to leakage, and decking boards may also be made from wood that is subject to damage over time.
Once water penetrates a garage’s foundations and structure, rotting can weaken the entire roof. The roof may then sag, causing water to collect instead of draining away as it should.
Avoiding this situation is a good idea both in the short and long term. But what can you expect to pay?
In this article, we’ll cover how much you can expect to pay to replace a garage roof and other common questions around garage roof replacement.
Average Cost of Garage Roof Replacement
The average cost of a garage roof replacement depends primarily on the roofing material used. Added extras like new guttering or fascias will bump up the costs. When you’re replacing the main roof material, it’s usually economical to replace other components as well.
It depends on the state of your roof and what your roofer recommends. Get a quote for different types of roofs and added extras. If you can safely get on your roof then go and have a look yourself.
Other costs to factor in are:
- Decking boards
- Insulation upgrades
By taking quotes from 7 roofers and 6 secondary sources, we discovered the following average garage roof replacement costs.
|Material||Single Garage Roof||Double Garage Roof||Pitched Roof (Tiles Only)|
|Tiles (Slate or Concrete)||N/A||N/A||£5,000+|
Costs are broken down with extra costs for decking boards, insulation, etc below.
|Single Garage Roof||Double Garage Roof||Pitched Roof (Tiles Only)|
|With OSB Decking Boards||+£250||+£450||N/A|
|With Insulation Upgrades||+£350||+£600||+£750 minimum|
|With Flashing, Fascia Boards and Guttering||+£300||+£500||+£500 minimum|
As we can see, replacing a garage roof for under £1,000 is possible if you literally just replace the felting with new felting and leave everything else intact. From there, the cost scales with different materials and extras like flashing, guttering and fascias.
It’s often a good idea to upgrade more than just the covering of the roof, especially if your decking boards are dated.
Choose a roofer with a solid local reputation, someone who is preferably part of the Roofing Competent Persons Scheme. Look for a solid portfolio of recent work.
Listen to your roofer’s guidance on what you should/shouldn’t replace, but don’t be forced into replacing more than you feel is necessary.
It’s worth mentioning that EPDM rubber roofs are linked to cowboy roofers, namely because it doesn’t require much specialist equipment to fit and there’s knock-off rubber available. Don’t accept chance offers of quick, cheap roof replacements.
Removing Asbestos Garage Roofs
One major consideration is whether or not your old roof is made from asbestos.
Either the tiles or insulation decking boards may be asbestos. If you wish to remove old asbestos roofing materials then you must use a Health and Safety Executive (HSE) registered contractor. HSE maintains a list of companies that are licensed to remove asbestos.
Locating a specialist asbestos removal should be fairly straightforward. Here are the average costs of removing roofing asbestos.
It’s worth knowing that many roofing tiles look like asbestos but are actually concrete – so don’t panic if your roof has that characteristic asbestos off-grey tone!
Never attempt to remove or disturb asbestos yourself. It is relatively safe if it’s undisturbed and some types of asbestos are safer than others, but the stakes are too high.
|Type of Material Removed||Single Garage Roof||Double Garage Roof||Pitched Garage Roof|
|Removing Asbestos Tiles||£400||£700||£1500|
|Removing Asbestos Decking Boards/Insulation||£800 - £1000||£1500 - £2000||N/A|
Types of Garage Roofing Material
There are 3 types of garage roof material for flat roofs; felt, rubber and fibreglass. Pitched roofs will usually be tiled, but there are synthetic products on the market now.
Felt it the classic roofing material that has been in use for close to a century. Bitumen felt is cheaper, strong and waterproof. It’s pretty simple to fit, can be patched cheaply and modern felt outlasts older felt by a considerable margin. Modern felt roofs should easily last 15 years without much maintenance.
Felt roofs come in either 2-layers or 3-layers. It’s best to fit felt over OSB wooden decking boards. Replacing old felt roofs with new decking boarded felt roofs is quick, easy and cost-effective.
Pros of Felt Roofs
- 3-layer systems are highly durable
- Easy to repair and patch
- Quick and painless job
Cons of Felt Roofs
- Not as long-lasting as other options
- Poor aesthetic appeal
- Rarely able to bear weight (depending on the rest of the roof)
Flexible, waterproof, hardwearing and easy to fit, EPDM rubber is a solid alternative to felt and probably outlasts it under most conditions. It’s pretty much just black rubber that can be rolled across the roof and sealed. EPDM rubber fitted as a ‘one-piece membrane’ is a good modern alternative to felt, but it doesn’t look much better.
Pros of EPDM Rubber Roofs
- Lightweight and durable
- Easy to fit
- Suitable for small or large roofs
Cons of EPDM Rubber Roofs
- Doesn’t look great
- Needs to be fitted well to work properly
Fibreglass is a more expensive option that looks good, is hardwearing, strong and pretty easy to fit. Like felt, it needs to be fit over OSB boards. It’s a more expensive job but you can expect it to last longer than felt. Modern fibreglass has excellent fireproof properties. Fibreglass is pretty slippery when wet, however, and isn’t always suitable for very large garages.
Pros of GRP Fibreglass Roofs
- Hardwearing and durable
- Looks good
- Very watertight
- Range of styles available
Cons of GRP Fibreglass Roofs
- More expensive option
- Not suitable for large roofs
If you have a pitched roof, then tiles are the most likely roofing material. Tiles are the classic material for angled roofs, but they’re not suitable for flat roofs.
Replacing tiles is a different ballgame to replacing flat roofs, and the cost will be considerably higher, especially if you need to replace the entire roof. This would be rare, however, unless you’re looking to replace an old asbestos roof – more on that shortly.
Roof Replacement and Building Regulations
The vast majority of garages have flat roofs. Flat roofs must be built to a certain specification to meet Building Regulations.
Namely, the Codes of Practice specified in BS6229 and BS8217 specify a minimum gradient of 1:40 and a maximum gradient of 1:80 depending on the size of the roof. This ensures that rain will properly drain from the flat roof.
Furthermore, the Planning Portal specifies that any work that replaces more than 25% of the roof will have to be accompanied by an upgrade to roofing insulation to meet current regulations.
You will not need Planning Permission to replace a garage roof unless you wish to make structural alterations to the roof. If you replace the tiles on a pitched roof then these must match the tiles of the home’s main roof, or the existing garage roofing tiles.
To simplify the process of submitted clearance to Build Control, choose a roofer that is registered under the Roofing Competent Person Scheme. They will be able to self-certify that the work is compliant with Building Regulations.
Initial Considerations: Can You Repair?
Unless you’re able to inspect your roof yourself, you’ll need a roofer to have a look. This should only take a few minutes – an experienced roofer will be able to make a quick assessment of the condition of the roof.
If you already know your garage is leaking, e.g. by discovering a visible leak or wet patch in your garage, then you really ought to get it sorted out ASAP. Rotting to good-quality timber does not happen overnight, so there’s a good chance that your garage will remain structurally sound, even if you do discover an internal leak.
Of course, you should take quick action to sort the roof if you do discover a leak in your garage.
Here are 4 of the main roof problems
Sagging occurs when the roof sags inwards, preventing rainwater from running off correctly. This results in pools that accumulate on the roof. The solution to this is usually to replace decking boards, upgrading to OSB where necessary. Re-roof with felt or another choice. Sagging likely results in a full roof replacement.
Rainwater Drains Poorly
Rainwater might accumulate at the side of the roof, or might drain the wrong way onto a neighbour’s roof or similar. The roof will likely need to be relaid with new OSB decking. Improper drainage may benefit from a full roof replacement.
The Water Drainage or Guttering Has Failed
Drains require regular cleaning and maintenance. You might simply need to clean the drains or widen any outlet holes. Fitting leafguards may also improve the problem. Poor guttering or other lesser drainage problems or obstructions can often be solved by repair rather than replacement.
Leaking is the most alarming sign of a leaking or failing roof. Leaks may or may not be obvious, so stay vigilant of puddles or wet walls in your garage. Leaky roofs can rot the timber garage frame. Water droplets and condensation could also damage electrical equipment, causing a possible fire risk.
Get Prices on Removing a Garage Roof Near You
We’ve done our best to give you a good idea of what you can expect to pay to remove a garage roof.
However, our guides are not a substitute for a fixed quote specifically for you.
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