In my world there is a city built on a mighty river just as said river opens up into a marsh as it hits the sea. The river is quite wide and deep and when it reaches the city has already crossed a continent.

My question is what materials would the local buildings be made of?

The city itself is a quite large and wealthy trading city and is built on and around a canal riddled island. The nearest mountains are about 125 miles away, and the nearest source of wood is a bit closer. The technology is medieval but reasonable anachronisms could be permitted. So would the city rely on imported materials? Or are there local ones it could use?

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    $\begingroup$ Look no further than Venice, Italy for what such a city would be built of. $\endgroup$ – RonJohn Aug 4 '18 at 14:52
  • $\begingroup$ Venice isn't built on a marsh. $\endgroup$ – user49466 Aug 4 '18 at 15:42
  • $\begingroup$ @user49466 but it is built on water, and marsh is nothing if not watery. $\endgroup$ – RonJohn Aug 4 '18 at 16:47
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    $\begingroup$ "What Would The Buildings In A City On A Marsh Be Made Of?" Death... from all the malaria, yellow fever and any other mosquito-borne diseases you can think of. $\endgroup$ – RonJohn Aug 4 '18 at 16:49
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    $\begingroup$ Look as New Orleans. $\endgroup$ – pojo-guy Aug 4 '18 at 21:03

A medieval city wouldn't build on marshland.

Archaic humans regularly drained marshland, especially to use the fertile soil. If that's not what's happening, they'd built this on a coast, not in a marshy delta

To do this properly you'd need modern technology, not only to use appropriately rot-proof materials, but to sink any supports you need, deep into the earth. Imagine a town on top of an oil-derrick. That.

You'd need a piledriver: https://en.m.wikipedia.org/wiki/Pile_driver Capable of reaching a suitable foundation.

And rather than an area of firm ground that you build houses on (houses on an oil derrick), these people would build a stilt-town, with seperate pilings for each building. They'd use rope and plank walkways between buildings and boats/canoes/kayaks to get around, otherwise.

That's more reasonable, but again, they'd need a good reason to do this.

But lets put that aside, and assume that there's some really, really, really, important reason why they want to build a town, and they want it here. They'd use rot-resistant woods. Which wood depends on where they live:

*Domestic Species

Exceptionally resistant: black locust, red mulberry, osage orange, and Pacific yew.

Resistant or very resistant: old-growth bald cypress, catalpa, cedar (either eastern or western red cedar), black cherry, chestnut, junipers, honey locust, white oak, old-growth redwood, sassafras, and black walnut.

Tropical Species

Exceptionally resistant: angelique, azobe, balata, goncalo alves, greenheart, ipe (iapacho), jarrah, lignumvitae, purpleheart, and old-growth teak.

Resistant or very resistant: aftomosia (kokrodua), apamate (roble), balau, Spanish cedar, courbaril, determa, iroko, kapur, karri, kempas, American mahogany, manni, secupira, and wallaba.*


  • $\begingroup$ At least one medieval city was built on marshland, blame it on the Romans for placing it where it is, but London is basically built on a marsh. $\endgroup$ – Separatrix Aug 4 '18 at 15:46
  • $\begingroup$ Fair enough, but it's also heavily embanked and many tributaries are underground. Which isn't possible in the alluvial fan of a literal river delta. $\endgroup$ – user49466 Aug 4 '18 at 15:55
  • $\begingroup$ That's taken many centuries of development, the main embankments are Victorian and later, the rivers covered over in much the same period. $\endgroup$ – Separatrix Aug 4 '18 at 16:06
  • $\begingroup$ It should be noted that the British have a fine history of calling the Dutch to do that sort of work, now there's a nation who know how to build on a marsh. $\endgroup$ – Separatrix Aug 4 '18 at 16:09
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    $\begingroup$ Wood pilings and supports are absolutely fine underwater or soggy ground. As long as the wooden beams are not exposed to oxygen...then it starts to rot. I believe it was Winchester Cathedral, UK, that had shallow wooden foundation beams in waterlogged peaty soil. The weight of the building and the fluctuating water levels (allowing the wood to rot) threatened to topple the building, until the foundations could be reinforced by a single deep sea diver, and later by a team of bricklayers! $\endgroup$ – EveryBitHelps Aug 4 '18 at 19:05

Other answers make sense. What about something still realistic but more fantastic?

City of Ships

ship become building https://link.springer.com/article/10.1007/s11457-013-9116-2

Ships and boats, both intact and disarticulated, have been reused as port and harbor structures for at least the last two millennia. Based on the many available examples, it is now possible to analyze the reuse of ships within the larger context of harbor structures as a form of vernacular architecture.

A port city like this would have lots of ships coming and going. A ship is basically a floating building - it could be used as a whole for a land based structure or its components disassembled and used for construction purposes.

from The Reuse of Vessels as Harbor Structures: A Cross-Cultural Comparison. Journal of maritime archaeology. , 2013, Vol.8(2), p.197-219. Sorry I could not find free full text link:

The next known examples of reused timbers date to the twelfth and thirteenth centuries and come from Billingsgate and the Custom House Site in London. One of the Custom House boats consisted of articulated bottom and side slabs from a barge-like vessel dated to 1160–1190. The slabs were reused as part of a revetment, with their outboard sides facing the river and supported by posts and raking struts. At least one of the posts was also a ship timber, but its treenail pattern differed from the slabs, indicating it was likely from a different vessel (Marsden 1996: 41, 53, 116). The Custom House Site also produced a thirteenth-century vessel that had been split down the keel with the still fastened planking of either side incorporated into the revetment (Marsden 1981: 14).

Your city would be more fantastic, with ships of different ages and nations used entire as buildings. Ships could be stacked on top of older ships. Ropeways and webbing would be strung from building to building, using the old masts. Remnants of the ship's prior lives would be evident, as in the above image where the masts are still up and used as laundry lines. Some ships would be unusual, with their histories forgotten.

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    $\begingroup$ Love this answer. +1 $\endgroup$ – user49466 Aug 4 '18 at 21:03

Brick can be made locally. Swamps can be drained.

Mesopotamia, Lower Egypt (especially Alexandria), Venice, the Netherlands, London, and Tenochitlan are all examples of regions or cities built in low-lying areas with high water tables, using ancient or medieval technology.


Like any city, it's built out of whatever is available in the local area. If the city is on clay, it's built of brick. If the city is near stone, it's built of stone. If there's wood and mud then it's build of timber frames with wattle and daub. If there really is nothing then it may be a tent city.

The wealthy will import building materials, just to show off their wealth, but the bulk of buildings will use the local materials.

One of the things that gives historic cities their individuality is that they were always built out of local materials. London brick is a different colour because of the London clay. Bath is built of bath stone etc.

  • $\begingroup$ According to your answer, "the Buildings In A City On A Marsh" would be made of... marsh. $\endgroup$ – RonJohn Aug 4 '18 at 16:46
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    $\begingroup$ @RonJohn, if you'd read the question you might have noticed that there's wood available, you can also use reeds and well, mud. Take your pick, but there's plenty to build with if you keep an open mind. $\endgroup$ – Separatrix Aug 4 '18 at 16:54
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    $\begingroup$ If that's what there is, that's what you build out of. Mudbrick is as common a building material as any across the world, even for large wealthy trading cities. $\endgroup$ – Separatrix Aug 4 '18 at 17:06
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    $\begingroup$ @RonJohn, Cairo, Megiddo, Djenné Mosque is possibly the finest existent example. $\endgroup$ – Separatrix Aug 4 '18 at 17:47
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    $\begingroup$ @RonJohn, they're places where the only building material is mud, so they used mud. $\endgroup$ – Separatrix Aug 4 '18 at 17:53

In Iraq, people have built using reeds that grow in the marshes: enter image description here


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