UK may allow "upfilling"- building homes on rooftops

Didden Village
© Didden Village, Rotterdam, MVRDV

Is this an answer to the problem of affordable housing?

In any older city, there are acres and acres of roofs that could be green, covered in solar panels or, in fact, more housing units. According to Alex at the Micro Life, it may soon be legal in the UK to add housing units on top of existing blocks of flats (apartment buildings), houses, shops or offices.

"The answer to building new homes isn’t always an empty plot, or developing on a derelict site," Housing Secretary Sajid Javid said. "We need to be more creative and make more effective use of the space we already have available. That’s why we are looking to strengthen planning rules to encourage developers to be more innovative and look at opportunities to build upwards where possible when delivering the homes the country needs."

Two levels could be added, "in keeping with the roofline of other buildings in the area." This is what some have called "upfill housing" as opposed to infill.

One developer told a real estate site that it could boost housing supply and bring down prices for first-time home-buyers.

We fully welcome any move to increase housing stock – the market is in crisis with a severe lack of available properties, which is pushing prices up and pricing first-time-buyers out of the market. The fact that this will enable existing residential areas throughout the UK to expand is especially welcome, as it should increase stock in the areas which most need it, rather than being confined to more expensive urban areas.

Claire street© Richard Rogers and Tonkin Liu

I wouldn't be so sure about affordability though. We have shown a few rooftop additions and they are almost all incredibly high-end because it is really expensive to do. When I did one as an architect many years ago, it was never-ending:

  • Prove the foundations can bear the extra load
  • Reinforce building for earthquake and wind loads
  • Extend all fire stairs
  • Replace all existing fire doors to stairs on all floors
  • Reinforce roof
  • Calculate snow loads on adjacent roof and reinforce it if necessary
  • Install new full building fire alarm system
  • Relocate rooftop equipment

The zoning bylaw may have permitted it, but the building code (and the inflexible plan examiners) made it almost impossible. When we covered First Penthouse, a British developer that adds prefab penthouses, I wrote (in 2005!) "fully half of the budget is taken up by purchasing air rights, contractor fees for installation and other charges. Treehugger likes pretty things, but $ 1,500 per square foot?" Now, of course, that would be a bargain.

Kensington Market LoftsGoogle/ Kensington Market Lofts /via

On another project I worked on as a real estate developer, we had to reinforce all of the columns, but as the entire building was being renovated, it was not such a big deal. But it certainly didn't create more affordable housing; being penthouses with great views and higher ceilings, they were the most expensive units in the whole complex. This will likely always be the case; it is likely that Housing Secretary Sajid Javid has just created some very fancy penthouses.

Loft Cube© Loft Cube

On the other hand, imagine if supermarkets and stores with big flat roofs could be reinforced to accommodate whole communities of tiny houses and Loft Cubes. That could open up all kinds of opportunities.

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