Author: icwhy

Baggy tousers, dirty shirt, pulling hair and eating dirt. So much learning happens through play. Einstein branded it the highest form of experimentation. But in recent decades, time devoted to unstructured play has declined. As has eating dirt, which we now know can be good (in small amounts) for a kid’s microbiome. PlayDay is just one of the many initiatives aimed at reversing that trend. And it stands for something (see the graphic).

So, how can the built environment grown-ups lend a hand? Here is my two-penneth, from a building physics point of view.

Sun

• Map sun and shade over the day and seasons for your site, then zone the playground accordingly (e.g. “winter sun / summer shade” areas, “cool refuges”, “active sun zones”)
• Shade using groups of deciduous trees. Groups of planting are better for tree health, kids prefer them, they aren’t counted on your BRE shady amenity place check but do provide shade.
• If you really want to cool the area, you’re looking at 30-50% canopy cover. Go-on, I dare you.
• Stay away from high thermal mass ground cover and dark colours and mental things. Touch temperatures Prioritise high‑albedo, low‑thermal‑mass surfacing (light rubber crumb, pale resin‑bound gravel). Dark EPDM, metal slides and handrails can exceed safe touch temperatures in direct sun, creating burn risks. As if that wasn’t enough, hard surfaces amplify noise, which affects comfort and supervision. Soft landscaping can be added to reduce reverberation.
• Use low emisitivy, light cloured (but not shiny) materials, e,g, timber, especially in sundrenched areas.
• Avoiding glare from metal slides and bright plastics which can cause specular reflections; use matte finishes and avoid slides pointing south.

Wind

• For playgrounds near roads, maintain ≥10–15 m separation or use vegetation barriers with porous canopies to enhance pollution dispersion.
• Ensure that planting and fencing still allows 0.5–2 m/s air movement. Fully enclosed courtyards can trap warm air and raise MRT.
• Break up solid barriers and choose planting of appropriate heights e.g. crown height minimum 3m for trees, to avoid stagnant zones. Recessed corners, high fencing, and dense shrubs can create low‑wind pockets that increase heat stress.
• Use evergreens in the predominant winter wind direction to reduce winter windchill.

Rain

• Permeable surfacing — SuDS‑compatible surfaces reduce puddling and evaporative humidity. Wet rubber surfaces increase slip risk and prolong cooling times.
• Drying time modelling — Timber play structures retain moisture; orient them for morning sun to accelerate drying and reduce mould growth.

Other Guidance

We’ve put together a list of a few of our favourite online sources on this topic

From Canada a wonderful comprehensive design guide

Also from Canada, a reort on thermal comfort in playgrounds, bearing in mind the extremes of that climate

Some London outdoor thermal comfort design advice

The Town and Country Planning Association Children and Young People has more guidance on play provision in the built environment

Find more on Playday here

Natural light. The source of energy that’s essential for so many processes in our bodies. An influencer on our mood and free source of light and heat. If we’re not careful, however, it’s an extreme source of discomfort from overheting or glare. So, in the built environment, what does good daylight/sunlight design mean? Designing with the sun means getting the geometry right to harness useful solar energy and block unwanted solar gains for interior and exterior spaces around buildings, throughout the year.

INTERIOR: Let’s start inside. Good natural lighting is high on the list of what people look for in a home. So, here are the ingredients for getting it right.

Orientation. Keep the main axis running East-West-ish, so the building is facing within 30 degrees of south. Main living areas should be on this facade.

Window position: keep them high in the wall to throw light as far into the room as possible. Horizontal windows disperse light around a room and function better than vertical ones, all things considered (e.g. ventilation, view, desirable solar gain…). The height of the window influences the distance into the room at which good daylight can be achieved.

Floor plans should be limited by the rule of thumb for room depth: good daylight will be achieved at a distance into the room of 2 times the window head height for an unobstructed window e.g. if the window head is 2.5m, the daylight will be sufficient up to 5m into the room.

Window size: affects heat loss and useful solar gain, view and ventilation and really depends on the individual building and its surroundings. 25% of the facade is a reasonable stating point.

Glazing type: We ask a lot of the glass in our windows. We want it to keep heat in sometimes and block it’s arrival at others; it needs to let us see out and illuminate the room. The glazing’s g-value tells us how much solar heat it lets through. It’s different from it’s visible light transmission (VLT) which tells us how much light reaches inside. Low g-values are promoted to guard against overheating. However, we need glass to allow in useful heat gains in winter and there is now extensive research showing the importance to human health of some of the wavelemgths this glass may cut out. Broadly speaking, the more pains of glass, the better for heat loss but the more good wavelengths are cut out. The industry is just waking up to this so for now, choose a glass with g=0.5 or 0.6 and visible light transmission of 0.7.

EXTERIOR: use of water features and planting (such as green roofs, green walls, trees and shrubs) can lower local indoor and outdoor temperatures and ease the urban heat island effect. These strategies work best alongside building‑level measures that limit solar gain.

Solar Absorption or Albedo: extensive dark, hard surfaces should be avoided because their low albedo means they absorb more solar radiation and raise surrounding air temperatures. Re-radiation of heat from hard surfaces can be the main source of overheating in urban spaces.

Spacing: if developing a group of buildings, use the rule of thumb for: ows a distance of 1,5 times the building height reduce heights to the south to preserve solar access further north where the tallest buildings should be.

Shading: South-facing windows not shaded by their surroundings will need horizontal shading to cut out high-angle summer sun but let in much-appreciated winter sun. Rule of thumb for overhang length: half the height of the window. East and West facing glazing needs vertical shading to block highly penetrating, direct low angle summer sun, Where shading is needed, use external, moveable shading (see here)

Courtyards: lower heights in the south is important for courtyards which also need gaps to ensure some winter sun gets through and the interior isn’t in shade all year round. Use deciduous tree to the north of courtyard spaces to create deliberate summer shade and coolth.

Balconies should be the sticky-outy type and staggered up the facade, not one above another.

Playgrounds: make sure that sun will fall on them during colder weather. Deliberately create shady areas (several small ones is better than one big one), Ideally, consider tree planting which will create dense shade as it matures. Do not, repeat DO NOT use hard surfacing. Ideally, the hole area willprovide access to dirt on the floor but particularly ensure that the ground spaces receiving sun in the summer are shaded in summer. The recommended guidance is for at least 50% of the playground to receive direct sun on the equinox (not counting trees) but more is better. Double check the solar access for 9-3 on a winter weekend when it’s likely to be used.

Gardens: again, at least half the space should receive sun on the equinox but gardeners will thank you for more. Plant for shade and water retention

Planting: trees can be used to offer additional shading for buildings and public spaces. Deciduous species provide summer shade but allow winter solar gains once the leaves have fallen. Select species for drought resistance canopy cover, canopy density and crown height over 3m. Groups of trees are better than one. If you’re aiming to reduce the temperature of an area (e.g. playground or neighbourhood block) significantly, the canopy coverage needs to be 30-50%

The blackberries have peaked so a new school year must be round the corner.

Bursars trying to balance their books will continue to be challenged by high energy prices, so this week I’m dusting off the results from pilot studies we ran with five London primary schools a few years ago, in case they come in handy. A three-point summary: (1) it is possible to make substantial savings on school energy bills at little or no expense; (2) involving the whole school was recommended by site staff, was linked to increased savings and has a host of educational benefits for teachers and pupils eager for experiential learning; (3) the construction industry and academia could (and should) benefit from the data produced by students from KS2 onwards.

The project was nice: keen university students, fresh from their course, were paired with an experienced engineer or architect, to study a primary school, and quantify ways to make carbon and financial savings from energy efficiency measures and renewables. They also looked a little at wider issues like comfort. Some schools signed up for assemblies, educational workshops and meetings with site staff and teachers which appeared to make a difference to their subsequent energy savings. It made a huge difference to the ease of data collection for the students.

It’s a while since I taught in a primary school. I imagine that teachers are even more pushed for time these days. The project aimed to make recommendations which wouldn’t add to teachers’ workload. With that in mind, the simplest recommendation assigned two keen students as monitors to reset the classroom after each lesson so that the need for blinds-down, lights-on was assessed each day.

I’d love to hear from anyone who has tried this. Happy to share more insights. Do get in touch.

Below is my first attempt at an infographic (graphic designers of the world, I salute you and apologise for the small font, there is much to say on this subject).

Plants are not be a heatwave cooling strategy which can be up and running today but they are effective and have many highly-desirable co-benefits. Many shrubs and trees are best planted in the growing off-season we’re heading into, so here is a summary of some practical actions which can be taken in the coming months to guard against extreme heat in future years. The long game. Hopefully there’s something amongst the five for anyone fortunate enough to have agency over their home or to be designing for others.

With so many perks when plants are used to address overheating, I wondered why they aren’t used for this purpose more often. The benefits that come to mind, on top of their shading and cooling abilities are air-quality improvements, increases to sustainable drainage area, boosts to mental health, enlargements to biodiversity habitat, carbon sequestration and possible local food production (how about, a sense of collective endeavour?). So, why isn’t this currently very widespread? One barrier is that plants aren’t (yet) welcome in compliance testing for daylight, energy use or overheating. Funny not to include these tried and tested living devices for sucking CO2 out of the air in the battle against there being too much CO2 in the air. My guess is that plants have been seen as temporary, unpredictable, maybe unreliable. This is something we need to overcome quickly. Thoughts on this, very welcome.

LinkedIn Post

Finland’s successful Housing First national policy asserts that having a good quality home is the basis for the other aspects of life (health, education, relationships….) to go well. Without a decent home, it’s hard for the rest to follow. It makes sense. Radio 4’s Rethink recently covered social housing which discussed this idea, presenting a case study of a high quality social housing scheme. Its developer emphasised good daylight levels and larger-than-usual windows, as features of high quality housing design desired by residents.

We know instinctively that daylight is good for us physiologically and psychologically. There is growing scientific evidence to back this up, (how about this wonderful paper making a direct link between daylight levels in homes and feelings of happiness) . There’s also growing research regarding the positive difference to be made by other perks of ample glazing such as a good view and connection with outdoors.

A glazed area doesn’t need to grow much to increase natural light levels from adequate to good. With joined-up thinking and design work, floor plans, shading and glass-to-solid ratios can be optimised, concerns regarding overheating and heat-loss can be minimised. So, how can we encourage good daylight levels from ample, well-designed glazing to become the norm?

For starters, here are some inspiring examples of social (or affordable) housing employing larger-than-usual windows.
Unity Place
Appleby Blue Almshouse
Central Somers Town

What a treat it was to see and hear an old friend and colleague at the Architects’ Journal Daylight in Architecture Conference a few weeks back. Hearing the case for a renewed appreciation of the health benefits of daylight was music to my ears. Ruth Kelly-Waskett spoke persuasively on the history of light in homes and how electric lighting altered our age-old relationship with daylight and the outdoors.

With mounting evidence from diverse fields such as neurology, healthcare, education (the list goes on) all pointing at the necessity of a daily daylight dose, its time for a reappraisal of our relationship with natural light. This is particularly important given that the amount of time we are tending to spend indoors.

Daylight ranks third on the list of homeowners’ priorities after energy bills and space. So, it’s about time, daylight rose up the agenda of design priorities. Health concerns around overheating, with their immediate effects on the body, have been used to determine opening sizes to date. The effects of a lack of daylight are more insidious. With a little joined-up thinking, even if the Building Regs don’t require it (yet), it is possible to consider overheating, energy consumption and daylight in the round. This holistic approach is what makes “good daylight design” and is certainly to be recommended.