13 Questions to Ask Before Building a Rooftop Terrace
Sky's the limit? An architect reveals everything you need to know about rooftop terraces, from councils to costs
Julia Fairley
15 November 2019
Chief Sub-Editor and Writer, Houzz Australia and New Zealand. I love design and architecture that is thoughtful, sophisticated and champions an element of the unexpected. Before graduating with a Bachelor of Arts at UNSW and becoming a journalist, I studied interior architecture. For over a decade I have interviewed inspiring creative minds from around the world to write about design in its many different forms. Recently, I have also become an accidental gardener, to everyone's surprise.
Chief Sub-Editor and Writer, Houzz Australia and New Zealand. I love design and architecture... More
If you’ve ever flirted with the idea of capping off your home with a rooftop terrace to take advantage of those beautiful views, you’re not alone. City-dwellers in particular are taking it up a level – literally – in a bid to capture extra alfresco space. Rooftop terraces are growing in popularity, from vast areas for entertaining large crowds to small slices of space for quiet mornings spent musing over the newspaper. Regardless of whether you have grand plans or a more modest dream of ‘going up’, ask yourself these 13 questions before you commit to designing a rooftop terrace.
1. What are the advantages of rooftop terraces?
A quick glance at these rooftop terraces reveals skyline views as a major advantage, but the perks are practical too. When well-built, rooftop terraces can be used year-round. This extra space could form an entertaining area with a breathtaking backdrop, a private breakout space or, if you don’t have a garden on a lower level, a rooftop terrace can come to the rescue as your main alfresco area.
A quick glance at these rooftop terraces reveals skyline views as a major advantage, but the perks are practical too. When well-built, rooftop terraces can be used year-round. This extra space could form an entertaining area with a breathtaking backdrop, a private breakout space or, if you don’t have a garden on a lower level, a rooftop terrace can come to the rescue as your main alfresco area.
Michael Montgomery, principal architect of MMAD Architecture, renovated this Fitzroy North home in Melbourne, Victoria, and incorporated a grand rooftop terrace (the entrance to which is pictured here).
“Inner-city locations will often benefit because homes are so closely built that the ground-level yards might only get direct sunlight for a limited period, whereas a roof terrace might allow all-day sun,” says Montgomery. “Depending on the orientation of your home, it might be the perfect place on a beautiful winter’s day if your backyard doesn’t get any sun.”
Tip: Live in an older home? It’s wise to use a builder who has experience working with period homes before designing a rooftop terrace.
“Inner-city locations will often benefit because homes are so closely built that the ground-level yards might only get direct sunlight for a limited period, whereas a roof terrace might allow all-day sun,” says Montgomery. “Depending on the orientation of your home, it might be the perfect place on a beautiful winter’s day if your backyard doesn’t get any sun.”
Tip: Live in an older home? It’s wise to use a builder who has experience working with period homes before designing a rooftop terrace.
2. What are the disadvantages?
The disadvantages are few and far between, providing your rooftop terrace is well-constructed, shaded, and doesn’t suffer from any dreaded structural or waterproofing issues. Their major drawback? “You might not use it as often as you thought,” says Montgomery.
“They’re typically not cheap, so make sure you get the most bang-for-buck use. Also, consider the impacts of overlooking into neighbouring properties – that may require screening. Changes to the aesthetic of the home and planning overlays might require planning permits, which could take a long time.”
Find an architect on Houzz near you to design a rooftop terrace that complies with your local council regulations
The disadvantages are few and far between, providing your rooftop terrace is well-constructed, shaded, and doesn’t suffer from any dreaded structural or waterproofing issues. Their major drawback? “You might not use it as often as you thought,” says Montgomery.
“They’re typically not cheap, so make sure you get the most bang-for-buck use. Also, consider the impacts of overlooking into neighbouring properties – that may require screening. Changes to the aesthetic of the home and planning overlays might require planning permits, which could take a long time.”
Find an architect on Houzz near you to design a rooftop terrace that complies with your local council regulations
3. Which homes suit rooftop terraces?
Most houses – as opposed to apartments – can accommodate rooftop terraces. “If the roof terrace is to be located at the front of the house, properties that have a high parapet (such as mid-period Victorian terraces or even Art Deco-era homes), or that have a high gable-end roof form (like some Edwardian era homes) are perfect for rooftop terraces,” says Montgomery.
“Their high, ornate parapets and ridge lines provide a screen from the street level that will mean minimal impact on the original street front.” Such was the case with this Fitzroy North house – look closely and you’ll spy a rooftop terrace hidden behind the original parapet at the top of the facade.
Most houses – as opposed to apartments – can accommodate rooftop terraces. “If the roof terrace is to be located at the front of the house, properties that have a high parapet (such as mid-period Victorian terraces or even Art Deco-era homes), or that have a high gable-end roof form (like some Edwardian era homes) are perfect for rooftop terraces,” says Montgomery.
“Their high, ornate parapets and ridge lines provide a screen from the street level that will mean minimal impact on the original street front.” Such was the case with this Fitzroy North house – look closely and you’ll spy a rooftop terrace hidden behind the original parapet at the top of the facade.
“Flat-pitched homes are great, but you will need to consider what the impacts of handrails and screens will do to the look,” says Montgomery. “Likewise, steep pitched-gable roofs are also good, where you can recess the deck into the roof and utilise the pitch of the roof as screening and handrails, which will have even less visual impact from ground level.”
Tip: Keen on utilising an existing wall, parapet or structure as a handrail or balustrade? Make sure it meets the building-code requirements and have it reviewed by a builder, architect or structural engineer first.
Tip: Keen on utilising an existing wall, parapet or structure as a handrail or balustrade? Make sure it meets the building-code requirements and have it reviewed by a builder, architect or structural engineer first.
4. Which homes are less suited to rooftop terraces?
With the exception of most – but not all – apartments, rooftop terraces can usually be worked into houses. “On smaller inner-city properties, a hip roof facing the street (such as old weatherboard cottages) might not be ideal, since you’re likely to make a major impact on the original house unless it’s set back far enough from view,” says Montgomery.
With the exception of most – but not all – apartments, rooftop terraces can usually be worked into houses. “On smaller inner-city properties, a hip roof facing the street (such as old weatherboard cottages) might not be ideal, since you’re likely to make a major impact on the original house unless it’s set back far enough from view,” says Montgomery.
5. What about council approval?
In Australia, local councils have their own rules and regulations governing rooftop terraces, so your architect will need to do some research before submitting an application, particularly if you live in a heritage area.
“Councils’ heritage advisors often talk about preserving sightlines to chimneys and other period details,” says Montgomery. “What better way to appreciate these details than to encourage home owners to sit amongst them with an outdoor area hidden behind the ornate parapets of the many Victorian terrace homes?”
Council planning policies typically dictate the minimum setback for any new upper-storey extensions to minimise the impact at street level.
Browse more gorgeous rooftop terraces
In Australia, local councils have their own rules and regulations governing rooftop terraces, so your architect will need to do some research before submitting an application, particularly if you live in a heritage area.
“Councils’ heritage advisors often talk about preserving sightlines to chimneys and other period details,” says Montgomery. “What better way to appreciate these details than to encourage home owners to sit amongst them with an outdoor area hidden behind the ornate parapets of the many Victorian terrace homes?”
Council planning policies typically dictate the minimum setback for any new upper-storey extensions to minimise the impact at street level.
Browse more gorgeous rooftop terraces
6. How much do rooftop terraces cost?
Montgomery warns clients that building a rooftop terrace is not a cheap exercise and explains that the price of each project differs wildly. “A finished roof deck (requiring additional structure, substrates, waterproofing, finished flooring, handrails, and so forth) is approximately 40 to 50 percent more expensive than if you were to build a trussed roof with roof sheeting of the same area,” says Montgomery.
“So as a very loose example, if a roof was going to cost you AU$80,000, to build a roof deck of the same size could be in the order of approximately AU$110,000 to AU$120,000.”
Keep additional costs in mind as well: the price of building stairs or access to your rooftop terrace, shade structures and other features you may want, such as planter boxes or outdoor dining furniture.
Montgomery warns clients that building a rooftop terrace is not a cheap exercise and explains that the price of each project differs wildly. “A finished roof deck (requiring additional structure, substrates, waterproofing, finished flooring, handrails, and so forth) is approximately 40 to 50 percent more expensive than if you were to build a trussed roof with roof sheeting of the same area,” says Montgomery.
“So as a very loose example, if a roof was going to cost you AU$80,000, to build a roof deck of the same size could be in the order of approximately AU$110,000 to AU$120,000.”
Keep additional costs in mind as well: the price of building stairs or access to your rooftop terrace, shade structures and other features you may want, such as planter boxes or outdoor dining furniture.
7. What’s the scope of the work?
Montgomery says that many clients underestimate the scope of the alterations involved, especially for period houses. “The extent of work is most often not a matter of removing the old roof, laying some waterproof flooring and job done,” he says. “You’re most likely going to need to install new structural beams and floor joists to carry the additional loads, meaning the entire roof and ceiling of the rooms below are likely to be removed and replaced.”
Every project is different so with luck on your side, you may find it relatively straightforward to build a rooftop terrace. However, even if it is straightforward, you are more likely to be embarking on major – rather than minor – building works.
Montgomery says that many clients underestimate the scope of the alterations involved, especially for period houses. “The extent of work is most often not a matter of removing the old roof, laying some waterproof flooring and job done,” he says. “You’re most likely going to need to install new structural beams and floor joists to carry the additional loads, meaning the entire roof and ceiling of the rooms below are likely to be removed and replaced.”
Every project is different so with luck on your side, you may find it relatively straightforward to build a rooftop terrace. However, even if it is straightforward, you are more likely to be embarking on major – rather than minor – building works.
8. What common challenges can arise?
Structural issues are common, especially with older houses. If an existing chimney, parapet, wall or structure of your home was originally braced by a roof that you since removed to make way for your rooftop terrace, you will need a structural engineer to review the changes.
Structural issues are common, especially with older houses. If an existing chimney, parapet, wall or structure of your home was originally braced by a roof that you since removed to make way for your rooftop terrace, you will need a structural engineer to review the changes.
“Such was the concern with the chimney at the Fitzroy North house, which required additional bracing once we removed the original roof,” says Montgomery.
The solution in this case was ingenious. MMAD Architecture designed this rooftop bar, which acts as structural bracing and stabilises the the chimney, while also providing a place to rest your drink when enjoying the sunset.
The solution in this case was ingenious. MMAD Architecture designed this rooftop bar, which acts as structural bracing and stabilises the the chimney, while also providing a place to rest your drink when enjoying the sunset.
9. What about waterproofing?
Even if you have a regular roof without a terrace, properly designed and installed waterproofing is a non-negotiable. Every site is unique so will have different challenges. This sunken rooftop terrace was originally a pool which, as you can imagine, had its own distinctive waterproofing concerns.
“Ensure there’s adequate fall to gutters and the gutters are sized correctly,” says Montgomery. “When in doubt, oversize your gutters because the one-in-100-year downpours are happening more like once every 10 years these days. Always have an overflow pop from your gutters and rainwater heads, just in case they fill up or get blocked. If you ever see your overflow pop with water coming out, it’s a sign that you need to investigate the gutters to make sure they’re clear of blockages.”
Tip: Ensure your builder allows for adequate flashing of old-to-new junctions.
Even if you have a regular roof without a terrace, properly designed and installed waterproofing is a non-negotiable. Every site is unique so will have different challenges. This sunken rooftop terrace was originally a pool which, as you can imagine, had its own distinctive waterproofing concerns.
“Ensure there’s adequate fall to gutters and the gutters are sized correctly,” says Montgomery. “When in doubt, oversize your gutters because the one-in-100-year downpours are happening more like once every 10 years these days. Always have an overflow pop from your gutters and rainwater heads, just in case they fill up or get blocked. If you ever see your overflow pop with water coming out, it’s a sign that you need to investigate the gutters to make sure they’re clear of blockages.”
Tip: Ensure your builder allows for adequate flashing of old-to-new junctions.
10. Tiles or timber?
Montgomery recommends giving close thought to your material selections, because the roofs of most buildings are brutally exposed to the elements from sun up to sun down.
“Tiled surfaces, which are generally low-maintenance, can get hot very quickly, then radiate that heat up to where you’re sitting and down into the rooms below,” he says. “Timber decking will need to be cared for more frequently, but is less likely to get hot underfoot. Likewise, glare from surfaces – be it other parts of your roof or adjoining roofs – have the potential to make a space less comfortable.”
Montgomery recommends giving close thought to your material selections, because the roofs of most buildings are brutally exposed to the elements from sun up to sun down.
“Tiled surfaces, which are generally low-maintenance, can get hot very quickly, then radiate that heat up to where you’re sitting and down into the rooms below,” he says. “Timber decking will need to be cared for more frequently, but is less likely to get hot underfoot. Likewise, glare from surfaces – be it other parts of your roof or adjoining roofs – have the potential to make a space less comfortable.”
“Tiles will need to be laid on screed and have a cross-fall to drainage. They’re also installed on top of the waterproofing, meaning they’re a bit more difficult to replace should any damage occur to the waterproofing underneath,” says Montgomery.
“Decking boards (and some paving tiles) can be laid flat and installed on ‘seats’ that allow water to flow through to the waterproof substrate, meaning the two are separated and easier to repair and inspect for leaks.”
Tip: Choose materials specifically designed for outdoor use and check this is covered under warranty.
“Decking boards (and some paving tiles) can be laid flat and installed on ‘seats’ that allow water to flow through to the waterproof substrate, meaning the two are separated and easier to repair and inspect for leaks.”
Tip: Choose materials specifically designed for outdoor use and check this is covered under warranty.
11. Is weight an issue if a rooftop terrace is landscaped?
Weight is always an issue regardless of whether or not you landscape your rooftop terrace. In most cases, you may need to consult a structural engineer as well as your builder, architect and other tradespeople involved.
One cubic metre of soil weighs over one tonne – this is a sizeable load that will need to be structurally factored in. Pre-plan where you will place planter boxes or potted plants. Or, to reduce the weight of the soil, consider using artificial turf for a light-weight injection of low-maintenance greenery.
Tip: Remember, your new rooftop will ‘settle’ over time, so ensure your builder allows for tolerances between old and new.
Weight is always an issue regardless of whether or not you landscape your rooftop terrace. In most cases, you may need to consult a structural engineer as well as your builder, architect and other tradespeople involved.
One cubic metre of soil weighs over one tonne – this is a sizeable load that will need to be structurally factored in. Pre-plan where you will place planter boxes or potted plants. Or, to reduce the weight of the soil, consider using artificial turf for a light-weight injection of low-maintenance greenery.
Tip: Remember, your new rooftop will ‘settle’ over time, so ensure your builder allows for tolerances between old and new.
12. Can rooftop terraces be shaded?
It’s an urban myth that rooftop terraces cannot be shaded, unless of course the type of shelter you want impacts sightlines from street level, a heritage facade, or your neighbours.
“In summer – even in the mildest locations – the roof can get very hot, so some form of shade is a must,” says Montgomery. “You’re likely to get the most use when it’s somewhere you want to retreat to all year round. Just remember to design the shading to allow for good cross-flow of air to keep the space cool.”
It’s an urban myth that rooftop terraces cannot be shaded, unless of course the type of shelter you want impacts sightlines from street level, a heritage facade, or your neighbours.
“In summer – even in the mildest locations – the roof can get very hot, so some form of shade is a must,” says Montgomery. “You’re likely to get the most use when it’s somewhere you want to retreat to all year round. Just remember to design the shading to allow for good cross-flow of air to keep the space cool.”
13. How often will you really use your rooftop terrace?
Montgomery cautions his clients to temper their grand dreams with a dash of reality. “Frequently, I have clients suggest putting in a rooftop terrace purely because they like the idea of having a huge entertaining space,” he says.
Montgomery cautions his clients to temper their grand dreams with a dash of reality. “Frequently, I have clients suggest putting in a rooftop terrace purely because they like the idea of having a huge entertaining space,” he says.
“Think about the location and access and the amount of times you would actually use it. Do you really see yourself walking up three flights of stairs – whilst carrying up all the food and drinks – every weekend when friends are over? I prefer to design rooftop terraces that are either located off another living space, or have a separate place to sit and relax that’s undercover,” he says.
If your budget allows, Montgomery recommends incorporating a small kitchenette and some storage so you can simply wash up plates and glasses, then store them on the spot. Remember, the less hassle a space is to use, the more often you will enjoy it.
Your turn
Have you built a rooftop terrace or are you longing to do so? Share your experiences in the Comments below, save your favourite images for inspiration, and like or save this story. Join the conversation.
More
Need some more inspiration for your alfresco areas? Read up on 5 Steps to Finding the Right Landscape Designer for Your Home
If your budget allows, Montgomery recommends incorporating a small kitchenette and some storage so you can simply wash up plates and glasses, then store them on the spot. Remember, the less hassle a space is to use, the more often you will enjoy it.
Your turn
Have you built a rooftop terrace or are you longing to do so? Share your experiences in the Comments below, save your favourite images for inspiration, and like or save this story. Join the conversation.
More
Need some more inspiration for your alfresco areas? Read up on 5 Steps to Finding the Right Landscape Designer for Your Home
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Great article! Thanks for using our image. Our rooftop terrace featured has one of the most amazing views in Melbourne. What a spot!