I'm building a map of a fantasy town and its surrounding area. I'm using Campaign Cartographer (CC3) for this and I'm striving for appropriate scale.

I know that, nowadays, the average outside wall thickness is of 30cm (12 in) while the inner wall range 10-20cm (4-8 in). Unfortunately, this average thickness is much influenced by AC usage and my folks have yet to invent AC, so cm is (mostly) off the table.

Therefore, I have looked into the past.

I know castle walls average 2 to 6 metres (7-20 ft), but that thickness is likely influenced by their defensive requirements so, again, I believe those numbers to be misleading and, therefore, they're also off the table.

Question: How thick with the outer walls be in a regular house made of...

  • stone

  • wood

  • adobe

Is there a pattern that would determine the increasing thickness of outer walls in houses with several floors? For instance, would a two-storey house have walls with the double thickness of a one-storey house?

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    $\begingroup$ Why not look at actual construction methods from a similar time period to your fantasy? E.g. since you mention castles, you might look at wattle and daub, cob, half-timbering, &c. $\endgroup$ – jamesqf Dec 24 '16 at 2:59
  • $\begingroup$ @jamesqf: That's what I'm doing. But I only find wall thickness references in the form of adjectives (thick, very thick, flimsy, ...) if there's a reference at all. I intend to have houses with several building materials (from the poor to the rich); and even if I am now working on a northern town, I will soon work on southern ones, so I might as well look at all materials, whether they're traditionally northern or southern. $\endgroup$ – Sara Costa Dec 24 '16 at 9:18
  • $\begingroup$ Short answer is that only with wood is it uniform for a given building, the base of an adobe or stone wall is usually much thicker than the top and timber built walls are traditionally dictated by trunk size not built to measure. $\endgroup$ – Ash Nov 7 '17 at 10:01

It Depends

I'm not sure if this will be of any help, but I assume this would change depending on what other materials were used in the walls. For example, if the culture has metal nails, that might change things.

On earth today, modern societies can still build very large structures using these materials. For example:

But, I doubt if such feats could easily be achieved 1,000, 10,000 or 100,000 years ago by all people of all economic classes, due to lack of computer-aided architectural planning, modern quality control of materials used, and all the accumulated architectural knowledge over time. Even if they could make it in previous times, they might need other advanced technology such as scaffolding, cranes, masonry, metallurgy, etc. to make such building possible.

Materials Matter

With all three materials, I assume the type of materials used would also greatly effect the thickness of the walls. For example, very weak woods like balsa would need to be very different thicknesses than woods made of Australian Buloke, which is considered to be the strongest wood on earth. The same would apply to stone: walls made of talc would be different thicknesses than diamond walls, or granite vs. limestone. With adobe, I imagine the same would hold true. However, I did find this quote about adobe building code in the US:

Adobe walls are load bearing, i.e. they carry their own weight into the foundation rather than by another structure, hence the adobe must have sufficient compressive strength. In the United States, most building codes call for a minimum compressive strength of 300 lbf/in2 (2.07 newton/mm2) for the adobe block. Adobe construction should be designed so as to avoid lateral structural loads that would cause bending loads. The building codes require the building sustain a 1 g lateral acceleration earthquake load. Such an acceleration will cause lateral loads on the walls, resulting in shear and bending and inducing tensile stresses. To withstand such loads, the codes typically call for a tensile modulus of rupture strength of at least 50 lbf/in2 (0.345 newton/mm2) for the finished block.

Environmental Factors

This might not be exactly what you are asking about, but in a sense, it might not be able to be avoided in a natural setting, namely other needs the wall must meet. For example, most walls need to do more than just hold up the roof or second floor. As you mentioned, medieval walls needed to provide defense, and modern walls need to house electrical wiring. If the building is in a very cold climate, insulation may be needed, and so if the insulation is placed inside the walls, that could change structural requirements. Or, as you mentioned, defense against hostile entities historically has changed walls. Or, earthquake prone regions would require different styles of walls. Frequent flooding, excessive heat, high winds, etc. would also effect wall structures.

  • $\begingroup$ I am aware of the factors you mention. I've been reading about it, but I can only find references to actual wall thickness for modern buildings and castles. Normal traditional houses... nothing. For instance, I've found a pdf for Portuguese students of architecture that compare modern building practices to traditional ones (despite being a small country we have a lot of different traditional housing techniques between North, centre, south, coast, hinterland). They mention average wall thickness for modern buildings and then just use the vague 'thick - thicker - less thick' terms for the rest. $\endgroup$ – Sara Costa Dec 24 '16 at 9:11
  • $\begingroup$ What makes you think that people did not have "scaffolding, cranes, masonry" 1000 years ago? In Europe, for example, there are Roman buildings still standing and in use, such as the Basilica of Constantine in Trier, Germany, or the Basilica of Saint Paul Outside the Walls, the Castel Sant'Angelo and the Pantheon in Rome. $\endgroup$ – AlexP Dec 24 '16 at 9:14
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    $\begingroup$ As for early modern houses (c. 16th century), there was an interesting technique that called for the second floor to have a timber frame structure which meant the first (ground) floor didn't need its walls to be much thicker to support the extra weight. Besides the timber frame, the walls weren'ts built exactly over the first floor walls, but more like a balcony, which also enlarged the house area. But again, the only referece to thickness I've found are adjectives, not numbers. It's all very frustrating. $\endgroup$ – Sara Costa Dec 24 '16 at 9:14
  • $\begingroup$ @AlexP My point was that although those things did exist in some places at some times, things like modern cranes were not widely available. The more you get involved with more common buildings in more rural areas, the less likely you are to have significant technology/architectural advancements to help in building. So, the average farmer in the middle of nowhere was less likely to have cranes pouring concrete footings for his foundation, whereas today, even middle class people have professional construction cranes available for building their homes. $\endgroup$ – Thom Blair III Dec 24 '16 at 10:11
  • $\begingroup$ @AlexP I mentioned only 1000 years ago as an example time period, and cranes, masonry and scaffolding as examples of technology that made construction more efficient. I've reworded that part to make my intentions more clear. $\endgroup$ – Thom Blair III Dec 24 '16 at 10:14

12th-century building regulations in London specified 3' thick walls when built of stone, though by later centuries stone party walls (walls held in common with several other buildings) being built 2' thick.

For houses built of timber, thicknesses varied, but the principle posts tended to be ~10-12" thick. A half-timbered house wouldn't have had walls thicker than its principle posts, so that's probably your thickness.



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