Talk:Key:roof:material

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Plants

I think the newly added value "plants" is badly chosen - it's impossible to tell from the value itself that it is supposed to represent a "roof" (I'm also not sure whether it can actually be called that) as shown in the picture. --Tordanik 14:51, 16 June 2013 (UTC)

That is not a roof at all.
But what about a green roof, (live) sod roof, living roof or, roof garden? Michael Z. 2014-10-09 21:26 z
I concur. Similarly, "gravel" - the gravel isn't the roof, it merely covers it. The roof is actually made of something else (e.g. concrete). --John Grubb (talk) 09:19, 4 September 2018 (UTC)
I agree. We should try to reach a consensus on how to tag green roofs. Green roof on Wikipedia. We should make the distinction between at least four types:
  • green_extensive (thin layer of soil, in northern Europe often planted with sedum - succulents)
  • green_intensive (thicker layer of soil, varied vegetation, higher price and possibly more maintenance)
  • roof_garden (Both for plants and for people to stay on)
  • grass (The traditional grass roof. could be classified to be a quite similar to the extensive roof, but the vegetation type is specified)
Also see two examples of mapping of green roofs :
-MortenLange (talk) 20:48, 5 August 2019 (UTC)


Default roof material

What is the default roof material? Presumably the same material as the building[:part] itself? --Abbafei (talk) 06:49, 29 December 2014 (UTC)

I don't think there is a standardized default material at the moment. My own implementation prioritizes the roof:material on the individual building:part, then falls back to that of the enclosing building, and ultimately defaults to a tiled roof. A case could be made to make the default dependent on the building material, or even the country/region instead. --Tordanik 17:41, 31 December 2014 (UTC)

Shade Cloth

Added shadecloth - used in warmer climates. As well as covering plants it is also used for play areas to reduce the exposure to sun light. Warin61 (talk) 23:00, 9 September 2015 (UTC)

Plastic, asphalt

Plastic (PE or similar) roofs are common to cover garden huts etc. here. I will add roof:material=plastic for this, it is already used 142x. It looks similar to roof:material=eternit, but it's usually partly transparent.

I also want to add a similar one to plastic and bitumen, but made of asphalt. This is similar to tar_paper, but it is usually corrugated, stronger and doesn't need the underside covered continuously (sorry, I couldn't find the English word). It is clearly distinct from tar paper. I propose material=asphalt, it has 90 uses in taginfo. --V0174 (talk) 11:46, 3 December 2016 (UTC)

I too am considering that tar_paper is perhaps too all-encompassing. In simple terms, in the UK a bituminous fibre-based sheet is placed on the roof before the tiles or slates go on (tar_paper) but when the bitumen-impregnated fibre sheet is used as the actual exterior roof material it is reinforced with the addition of asphalt and an aggregate layer, having a rough, hard-wearing texture and is known colloquially in the UK as roofing felt. Perhaps the addition of roof:material=roofing_felt (or similar distinctive tag) would allow for clear identification between the two materials? Whilst tar_paper does indeed cover it there is a significant distinction between sheeting intended to form an impermeable membrane beneath slates/tiles, etc. and sheeting designed to form the roof layer exposed to the sky.

https://en.wikipedia.org/wiki/Tar_paper https://en.wikipedia.org/wiki/Asphalt_roll_roofing (what in the UK is commonly colloquially referred to as "roofing felt")

Edit: A further thought occurs that, when roofing felt is applied it is usually over wooden boards or the like so presumably the correct tagging would be something like roof:material=wood, roof:surface=roofing_felt/tar_paper...? Second edit: see roof:structure proposal below. --John Grubb (talk) 04:54, 6 August 2019 (UTC)

--John Grubb (talk) 07:50, 2 September 2018 (UTC)

Asphalt Shingles

An asphalt shingle is a type of wall or roof shingle that uses asphalt for waterproofing. It is one of the most widely used roofing covers in North America.[1]

roof:structure

I recently re-read the building:material= section of the Wiki, having received a notification that the page had been updated, and note that it now refers to previously unknown (to me) tags of building:structure and building:cladding. Structure holds the material that the building is constructed from (i.e. load-bearing, be it brick, metal framing, wood frame, etc.) and Cladding holds the exterior finish (i.e. the decoration, such as rendering, stonework, brick facing, etc.).

Would it not then be natural and consistent to introduce roof:structure to the OSMWiki "roof" section for detailed building mapping, where the structure is known, alongside roof:material? I'm experimenting with roof:structure=wood_frame (based on definitions given for building:structure) with roof:material=slate/tile for slate/tile roofs built in the conventional British way using timber joists and rafters with a slate or tile covering. Other examples include agricultural barns where the building supportive structure is steel framing (building/roof:structure=metal) and the walls and roof are of metal and fibre sheets (building:cladding=metal, roof:material=eternit).

It seems important to differentiate in detailed mapping of buildings as roof:material=roofing_felt/tar_paper/grass/gravel/etc. implies that the sole load-bearing component is a somewhat flimsy material when the actual material is merely a covering with no structural support qualities at all (i.e. it is not really the actual fabric of the roof). --John Grubb (talk) 04:53, 6 August 2019 (UTC)

If you want to add data on what's beneath the top-most layer, a key like roof:structure probably makes sense. I would like to keep roof:material defined as the roof's outer material (historically, this arose in part because it was originally invented for 3D rendering, but also because the structure beneath isn't necessarily visible for a mapper looking at the building from the outside). But adding a second tag alongside it ... why not? :) --Tordanik 19:46, 9 August 2019 (UTC)
Thanks for the support! I'm thinking that roof:material would remain to define the outer covering that can be seen. roof:structure would just be an extension for fuller information. If the structure was not known then it would be omitted and roof:material given on its own.
In the UK at least, it's general practice for domestic houses to have wooden roof structures to support the slates or tiles whilst industrial buildings, agricultural barns and the like are built with a building:structure and roof:structure of steel I-section beams with a metal sheet building:cladding and roof:material (in this regard it would seem that building:material could stand for the outer surface where building:structure is used but I didn't write the spec for that one, so...). It gets more difficult where old medieval, Tudor, Georgian, etc. era buildings come into play because they are often built from stone, cob (adobe) and other less advance materials and techniques so it's not always a given that "hidden" construction can accurately be assumed - or that outer finishes are what you might first think.
Another consideration is where cavity walls are not built with the same material for the inner and outer wall any more. I've watched a new estate of houses being built near me and the construction goes thus: poured concrete foundation, a couple of courses of cheap cement blocks, then a pre-cast concrete panel floor. The outer wall is then a couple of courses of nice brick where it will show and then back to cheap cement blocks. The inner wall is wood-framed and wood-panelled and dense foam sheets are placed in the cavity. The outer wall is then decoratively finished with rendering and the inner wall with plaster and paint. The roof is the conventional construction of wooden trusses, joists and battens with a covering of tar-based fibre material for water-proofing ("tar_paper" in OSM but more like roofing felt without the asphalt in reality) then the outer "roof:material" of slate or tile. Sometimes there is a non-functional (i.e. decorative) brick chimney.
How then to detailed-map that? Obviously, there's no need to create tags defining the entire component-by-component construction - that way lies madness! In the above example I would tag it roof:structure=wood_frame, roof:material=slate/tile with building:structure=cement_block, building:cladding=rendering and building:colour=white (assuming white render). The cement block part is the load-bearing component and thus the main "structure." In the roof the wood framing of the trusses is the main load-bearing part and is thus the "structure."
In building tagging where the structure/cladding combination couldn't be determined or it was obvious that the structure and outer finish were one and the same (e.g. an old cottage built from stone with no cavity) then I'd use building:material=stone and roof:material=thatch (for example) as there is no structure/cladding differentiation and the roof structure is unclear (although very likely to be wood_frame in this example). This potentially introduces an inconsistency of "mixed tagging" across the map where some buildings are tagged with structure and some with material to essentially describe the same component, and some buildings are not tagged with either due to "lazy" mapping or the item not being known to the mapper.
But I digress; back to roof:structure...
Okay, I give up! How do you link to an image in here...??!


Another variation example would be the small building - a garden shed, say - where the roof:structure is wood boards or sheets (e.g. plywood) so the roof material would be roofing_felt and the roof:structure would be wood rather than wood_frame, I should think - even though the wood sheets are attached to wooden battens and framing.
All good fun. Still, let's have a play with the idea and see where we can go with it.--John Grubb (talk) 05:15, 10 August 2019 (UTC)