The slab that is too hot in July and too slow to dry in November
Every change below is put into the plan and the whole model is run again. That is why a pergola's winter cost shows up here without anybody having written it down, and why the cheapest thing that works is allowed to win.
Reading at
Crossing it barefoot
Direct sun is15 over— 100 / 100 against at most 85
Sun on the crossing is only a problem because of what it has done to the slab for the last four hours.
Confidence low (37%). Treat this as a starting hypothesis, not an answer.
A 13.8 ft umbrella fixes direct sun.
Ranked by what solves the actual limit with the least effort, not by the biggest number.
Not offered, and why
A 13.8 ft umbrella fixes direct sun.
A 13.8 feet canopy at about 7.5 feet, tilted toward the low sun.
+0 hours of usable time on this day. Opens 9:00 AM to 8:00 PM.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
A deciduous tree 16.4 ft south-east of the seat fixes direct sun.
A medium deciduous tree planted 16.4 feet to the south-east, grown to about 26 feet, with a crown roughly 19.7 feet across.
+0 hours of usable time on this day. Opens 9:00 AM to 8:00 PM.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
An evergreen group behind the deciduous planting fixes direct sun.
A group of evergreens to about 8.5 feet set behind Dense deciduous tree. In summer it disappears into what is already there; in February it is the only thing standing between the seat and the view in.
+0 hours of usable time on this day. Opens 9:00 AM to 8:00 PM.
At this hour it removes about 85 per cent of the summer beam and about 85 per cent of the winter beam. The winter half is the part people regret.
Move the table 6.6 ft north-west does not move this in any way worth the effort.
Slide the seating about 6.6 feet toward the north-west and change nothing else.
+0 hours of usable time on this day. Opens 9:00 AM to 8:00 PM.
It does not meaningfully change the beam in either season.
A second seat 19.7 ft north-west does not move this in any way worth the effort.
Put two chairs 19.7 feet to the north-west and leave the main table where it is. The point is not to fix this spot but to stop needing it at the hour it does not work.
It does not meaningfully change the beam in either season.
Sit under Dense deciduous tree does not move this in any way worth the effort.
Move the seating under Dense deciduous tree, which is already standing and already casting something. Costs nothing and takes an afternoon of trying it.
It does not meaningfully change the beam in either season.
Two 8.2 ft parasols instead of one does not move this in any way worth the effort.
Two parasols about 8.2 feet across, set 7.2 feet apart along the table. Between them they cover a rectangle, which is the shape a table actually is.
It does not meaningfully change the beam in either season.
Two low shielded lights instead of one high one does not move this in any way worth the effort.
Add a pair of shielded 200 lumen fixtures at knee height near the seating, so the useful light is where people are rather than thrown across the garden.
It does not meaningfully change the beam in either season.
A shade sail over the seating does not move this in any way worth the effort.
A sail about 16.4 feet by 13.1 feet, set at about 9.2 feet and angled to shed water.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
A deciduous climber on tensioned wires does not move this in any way worth the effort.
Wires strung about 8.5 feet above the seating with a vigorous deciduous climber trained across them. In leaf it shades like a light pergola; bare, it gives back most of the winter sun a solid roof would have kept.
It does not meaningfully change the beam in either season.
Raise the bed 1.3 ft does not move this in any way worth the effort.
Build the bed up about 1.3 feet with free-draining material. Roots sitting in water kill more plants than the wrong hardiness zone does, and lifting the root zone out of it is cheaper and far more reliable than trying to make the ground below drain.
It does not meaningfully change the beam in either season.
A 8.2 ft awning does not move this in any way worth the effort.
A folding-arm awning projecting 8.2 feet from the house wall at about 8.5 feet, retracted out of season.
It does not meaningfully change the beam in either season.
Lift the crown of Dense deciduous tree does not move this in any way worth the effort.
Raise the underside of Dense deciduous tree from about 7.2 feet to 12.1 feet. Light comes in sideways under the canopy, morning and evening, without losing the shade overhead at midday.
It does not meaningfully change the beam in either season.
A pergola with open slats does not move this in any way worth the effort.
A pergola about 13.1 feet square at 8.5 feet with open slats, slats running roughly south-west.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
An adjustable louvred roof does not move this in any way worth the effort.
A louvred roof about 13.1 feet square at 8.5 feet, blades running south-west and closable.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
A paler paving does not move this in any way worth the effort.
Replace Mixed-exposure concrete slab with a paler paving of similar mass. The surface itself runs cooler underfoot; the trade is that more light bounces back up at a seated person.
It does not meaningfully change the beam in either season.
A solid canopy over the seating does not move this in any way worth the effort.
A solid roof about 11.2 feet above the seating, 13.1 feet by 11.5 feet, guttered on the low edge. Unlike fabric it works in rain, and unlike a pergola it takes the winter light too.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
Horizontal fins above the opening does not move this in any way worth the effort.
A run of fixed horizontal fins projecting about 2.3 feet from House, set above head height. Geometry does the work: high summer sun is cut, low winter sun passes under, and the view out is barely touched.
It takes the summer sun and leaves most of the winter sun, which is the behaviour worth paying for.
Relay it as a permeable surface does not move this in any way worth the effort.
Relay Mixed-exposure concrete slab as permeable paving or resin-bound gravel over an open sub-base. Water goes down instead of sideways, so the spot dries hours earlier after rain and stops holding the film that makes it slippery and green.
It does not meaningfully change the beam in either season.
A ventilated timber deck instead does not move this in any way worth the effort.
Replace Mixed-exposure concrete slab with a ventilated timber deck. Heavy paving charges all afternoon and radiates back until well after dark, which is why an evening terrace can feel hotter than the air. A light deck over an air gap is done within the hour.
It does not meaningfully change the beam in either season.
Take up the paving and plant it does not move this in any way worth the effort.
Lift Mixed-exposure concrete slab and plant it. Nothing else on this list moves surface temperature as far: paving in full sun sits twenty degrees or more above the air, while planted ground transpires and typically sits at or below it. It is also the only change here that gets better rather than worse over ten years.
It does not meaningfully change the beam in either season.