Building the Stronghold- calculating time

[derv]

I've been researching construction during the Middle Ages in order to come up with some general guidelines for building strongholds. I'd like to use the costs found in U&WA, but time for such construction is not given. In my reading, the construction of castles was limited to the Spring and Summer seasons from about April till the first frost (as late as November)- basically 6-8 mths. a year. Construction times of existing castles are estimated to have taken 2 to 12 years depending on size. Early timber structures are suggested to have taken as little as 4 weeks to build.

The DMG gives a little more guidance on page 106.
-excavation: 100' long, 10' deep, 20' wide takes 3-4 men 6 weeks.
-stone construction: 1 week per 10 cu ft. + quarry and transportation work
-wood construction: takes half the time of stone. 10' sections per day.

What would be the most helpful is establishing how many man-hours or man-days of labor each type of construction would require. This information is not easily gathered, so I formed a general conclusion based on total construction time involved per man at 10 hours per day. In other words, these estimates would include transportation, organization, and preparation of available resources in the overall time. Only simple calculations of area or volume divided by man power available would be required to come up with reasonable time estimates.

Earth work= 1 man day per 10 cubic feet
Timber construction= 1 man day per 10 square feet
Stone construction= 5 man days per cu. feet

If any one has some more accurate information that they could site, I'd be interested. I'm not completely satisfied with these estimates, because I'm trying to cover the bases of how castle construction evolved from the fortifield house (manor), shell keep, motte & bailey, to the concentric castles and cathedrals.

[Red Baron]

These of course are the time estimates that employed masons will give to the players.

Actual build time will be 1d3 times as long due to the usual problems associated with large construction projects.

((And don't forget to harass the builders with monsters, requiring the additional expense of guards.))

[Scott Anderson]

Idk what it is BtB. But we say the costs listed are to get it done in one game year. Double the money means it gets done in 8 months.

[derv]

What I'm shooting for is a general formula that allows for a variety of architectural options, depending on the setting. Options such as Stave Churches and the Scandinavian Longhouse. I want the players to have the option of erecting simple strongholds in short periods of time, such as Manor Houses or Motte and Bailey Castles.

This formula would not take into account the time necessary to clear adequate land or find laborers.

It seems to me, if the natural resources are available, the real determination of how long construction takes is man power and the money to support it. Man power will most likely be the most determining finite resource to be managed. The assumption in my campaigns will be that you only have the Spring and Summer seasons available for construction. All other intervening impediments during this time will be the result of possible random variables and their affects (severe weather, natural disasters, disease, raids & incursions, mechanical & structural failures, etc.).

Using my numbers above, a small wooden Motte and Bailey could be calculated:

Motte: 16' high x 50' wide
V= L x W x H = 50 x 50 x 16= 40,000 cu. ft.
C= pi x D = 3.14 x 50= 157 linear ft.

10' high palisade:
10 x 157= 1570 sq. ft.

Bailey: 40' long x 60' wide
(40 + 60)2 = 200 linear ft.

10' high palisade:
10 x 200= 2000 sq. ft.

Wooden Tower: 30' wide x 30' long x 30' high
(30 x 30)4 = 3600 sq ft.

40,000/10 = 4000 man work days for earthwork

1570 + 2000 + 3600 = 7170/10 = 717 man work days for timber construction

Total man work days = 4717

If you have 40 laborers (plus engineer)- 4717/40 = 118 work days (4 months) to complete structure.

[talysman]

Useful information!

I'm glad you're doing the work, but I think cubic feet and square feet are less useful than "dungeon standard" measurements based on map squares and standard heights of ten feet. Thee are 1000 cubic feet in a ten foot square/10 foot high structure, so earthwork takes 100 man days per full square, and stonework takes 5,000.

[Scott Anderson]

So how many man days is a horn of blasting worth? Or a spade of mighty excavation? Or a goblin conscript?

[derv]

Mar 29, 2015 14:06:33 GMT -6 talysman said:

Useful information!

I'm glad you're doing the work, but I think cubic feet and square feet are less useful than "dungeon standard" measurements based on map squares and standard heights of ten feet. Thee are 1000 cubic feet in a ten foot square/10 foot high structure, so earthwork takes 100 man days per full square, and stonework takes 5,000.

I don't consider my methods as scientific. I certainly know how to do things the hard way, it's how my mind seems to work

If you intend all construction to be rectangular, what you suggest will work. Once you start introducing circular and, especially, oval structures, things become a little more complicated. These calculations can be fudged, but when everything is considered, the results should bear out as reasonable in comparison to historical rates. I'm still vacillating on stone construction rates.

Mar 29, 2015 14:25:33 GMT -6 Scott Anderson said:

So how many man days is a horn of blasting worth? Or a spade of mighty excavation? Or a goblin conscript?

Not exactly sure what you're asking me Scott, but a goblin or kolbold conscript is worth half a man for all phases of construction. Dwarves and Gnomes are equal to 2 men for all earth works

[Porphyre]

Didn't JG Ready Ref Sheets have something about that ?

[derv]

Thanks Porphyre, I didn't remember that being in there. It's a very helpful recommendation.

For those interested, the Ready Ref Sheets give a formula of: GP costs/ 600 = Weeks/ 100 men.

As an example it gives a 30,000 GP tower taking 100 men 50 weeks to construct.

I'm not sure how realistic this rate of construction seems to be. They list a 40' x 40' round stone tower as costing 10,000 GP (same as U&WA). The example would be a very large tower being completed in under a year.

This also doesn't quite give the granularity that I was looking for when building small holdings, but there is some interesting info that's not found in the LBB's.

[tetramorph]

derv, I would roll with what the RRSs give us because of a.) precedence, and b.) ease of play.

It needs to be tough for players, but not so tough as to deter end-game play. It needs to "feel" plausible, but allow for the fantastical. With all that magic around, maybe some stuff just gets done a little faster than in the real world.

But I read you as wanting granularity for smaller projects. I get that.

But couldn't you just come up with your own cost sheet and then use the RRS formula for your smaller projects? Perhaps dividing by 100, or even 60, instead of 600, if necessary to keep it seeming like a reasonable amount of time.

Like building anything, the devil is in the details. It may take almost as long to build a nice cottage or manor house as a 30 foot tower because the former still requires all those details that make it livable (and folks actually cared about craftsmanship, beauty and detail back then) where as a 30 foot tower is a cleverly devised pile of stones so that you can see far away from the top and shoot at people (nice, warm, livable details not so necessary).

[derv]

Certainly people are welcome to use the formula given in the Ready Ref Sheets. That's why I presented the formula for those who don't own them.

Also, talysman presnted a simple way of using grids in calculating time based on my assumptions.

I'm trying to form a reasonable estimate using standard building calculations based on early building practices. Once I feel comfortable with these rates, it will be a simple matter of forming a time and cost sheet that absorbs the details of the devil.

Don't get me wrong, I'm under no illusions that costs in D&D are accurate reflections, but I don't think one needs to handwave the time requirements for building a structure too. To me, time is an important tool in the game.

I generally run low or no magic settings that are anthropocentric. I would say that I also lean more towards tribal or clannish cultural settings then fuedal. On top of that, I'm very tight fisted in rewarding huge amounts of treasure.

What does this mean? It means I want to be able to encourage players to start building low cost strongholds earlier in the game then name level. Thus, moving to the table top with miniatures earlier too. My thoughts aren't really on the Tower of London.

[aldarron]

Dave Arneson's Adventures in Fantasy has info/rules of the sort you seem to be trying to work out on pages 17 and 18 OF BOOK 1. It might also be helpful to reference the FFC rules on bridges, canals, roads, and ship building.

From AiF:

Basic Castle Types
Round Tower 25' Diameter:

8' high, 1000 GP, 30 days to build
35' high, 2000 GP, 60 days to build
70' high, 9500 GP, 240 days to build
105' high, 40,000 GP, 30 months to build
140' high, 70,000 GP, 60 months to build

Gate Towers (about 50' high), 6000 GP, 135 days to build

Curtain Wall (one section) about 50'-60' high, 3000 GP, 75 days to build

Tunnels 10' x 10' x10' section takes 100 men 1 hour and costs 2 GP. The same with wooden supports will cost 3 GP and take 2 hours. A regular dungeon (stone supports, walls, etc) 5 GP and take 3 hours.

Crews: 100 man crews of unskilled (peasant) labor costs 1 GP a day to hire. 10 supervisors (1 master, 2 journeymen, 7 apprentices) costs 2 GP a day.

When building in Woods add 10 % to Time and Cost

When building in Swamps add Triple the Cost and Time, including hiring.

In mountains, Double all Times and Costs, including hiring.

Slave Labor will Halve the costs but Double the Time, plus wastage.

[derv]

Thanks aldarron. I have been studying the FFC, but do not have AiF. It seems Arneson also uses the 100 man crew as his basic method for calculating time of construction. Good information all the same.

[derv]

Some source material that I've found interesting and helpful:

Sidney Toy; Castles: Their Construction and History, 1985

J.E. Kaufmann; The Medieval Fortress, 2001

Charles Stephenson; Castles: A History of Fortified Structures, 2011

Assorted web sites; Wikipedia, castlewales.com, and castles-of-britain.com

I've recently been reading through these books that I was able to get through our inter-library loan program. Really good history of fortification and some useful layout illustrations with dimensions.

[krusader74]

Here's a somewhat realistic example that doesn't use the costs found in U&WA...

Dover Castle, the "Key to England": It has a massive stone keep surrounded by a stone inner wall and a stone outer wall. Its dimensions are approximately:

The Great Keep:
- inside base dimensions: 100' x 100'
- outside: 130' x 110' (meaning two walls were 20' thick, two were only 10' thick)
- height: only 4 floors, 83' (or 95' -- I've seen both numbers quoted)

Inner curtain wall:
- eyeballing it, looks to be 1,000' circumference
- 14 towers

Outer curtain wall:
- 1 mile circumference
- 20 towers

Expenditures: It took 4 kings a century to build:
- Initial construction was done under Henry II and cost £6,500.
- Richard I made minor refurbishments costing £1,000.
- John made minor refurbishments costing £2,000.
- Henry III made a major upgrade costing £6,500.

To put these expenditures in perspective, the annual income for a king was only about £5,000.

Time: It's been estimated by scholars like Jeffrey Singman that if Dover Castle had been built in one shot, rather than sporadically over many decades, it would have taken 10 years to complete and cost £10,000. As you point out, work was only performed 2/3rds of the year, from April to November. During the winter months, workers would build temporary huts in the center of the castle. Each year, approximately 1/10th the height of the castle would have been built.

Methodology: Based on a variety of sources, I've tried to backward engineer construction costs, assuming (counter-factually) it had been constructed in a single effort. Basically, I started with the labor force used by Master James of St. George, King Edward's chief engineer. (Edward succeeded Henry III.) I maintained his wage rates, but I scaled the labor force by about 4/9 to make the workers' total income match the kings' total expenditures. Interestingly, Master James built 10 castles costing £80,000 and bankrupted England---toward the end, workers were paid in tokens rather than actual coins. Beaumaris Castle alone cost £15,000; it was built over a 35 year period (there were long recesses due to wars); and it was never completely finished.

Conversions:
£1 = 20 shillings
£1 = 240 pence

Labor breakdown:
 800 general labor, supervised by 8 masters
 150 masons, 2 master masons
 80 quarry men, 1 master
 10 smiths, 1 master smith
 2 carpenters, 1 master carpenter
+ 1 engineer who supervises the entire project
------------------------------------------------
= 1042 unskilled workers, 13 masters, 1 engineer
(As an aside, the Henry II's engineer was named "Maurice.")

Wage rates:
- Less skilled workers get paid 6 pence per week (or £1/40 per week).
- Masters get 4 shillings per week (or £1/5 per week).
- Engineer gets 2 shillings per day (some sources say 3) for 5 days a week (or £1/2 per week).

Time:
Work is done for 10 years. Each year, 1/10th the height of the castle is built. Work is only done 2/3rds of the year from April to November (workers build temporary huts inside the walls to occupy from December to March, but no work is done). There are 52 weeks per year.

Expenditures: Total project cost is therefore
           time                 * ( unskilled wage rate   + masters wage rate  + engineer rate)
= 10 years * 2/3 * 52 weeks/year * (£1/40 per week * 1,042 + £1/5 per week * 13 + £1/2 per week)
≈ £10,000

NOTE: These costs only cover the labor for building the castle and NOT the garrison of troops that the construction project will need for protection!!! In real life, if it takes 10 years to build your fortress, the construction site will sooner or later become a war zone, as your enemies attempt to subvert your efforts. This will delay construction and increase costs. And that initial estimate of £10,000 and 10 years will eventually become £16,000 intermittently over the course of a century!

[Scott Anderson]

Re: Dover Castle

What an awesome edifice. I lived in southeastern England for a couple of years, and got to visit the castle maybe three times. It is difficult to approach even in a car on modern roads. I cannot imagine what kind of effort it might have taken to approach on foot or horseback or with siege equipment.

The costs for construction seem right. But part of the reason it took so long to build is that castles were constantly evolving to meet the defensive needs of evolving warfare. Specifically, cannon came into use and got much better over the course of construction. When it was first built, Dover had a huge keep, vey tall. When cannon became commonplace, the keep was brought down to give a smaller target. Part of the reason is that additional curtain walls were added to the seaside approach as more money became available to fund construction.

Dover is not, as castles go, particularly large or fancy. But to be there and see it, and imagine how hard it must have been simply to approach it with the tools and equipment needed to breach it, and then to fight through the breach... It would have been an amazing effort.

Addendum: the location of Dover was so strategically beneficial that England carved bunkers out of the chalk cliffs beneath it to use as a command center during WWII. The bunkers are now a museum, and just as cool to visit as the castle.

[derv]

While bumbling around the web, I came across these older OSR resources at the Lost Pages blog. I think I'll be ordering hard copies of Burgs & Bailiffs I & II from Lulu while they have their 30% off sale with the code APRIL30. But, if you follow the link, the pdf's are free.

There's an article in Burgs & Bailiffs Warfare Too on the subject of this thread. The author Charles Taylor is a man after my own heart. He takes a similar approach to castle building as krusader74 took above, by backward engineering his figures from historic examples. What may be highly useful to some here is that he also created a spreadsheet that does all the work for you. If building stone fortresses is in your future, it's worth checking out.

[derv]

I'm basically content with my final figures. I've taken a different approach with stone construction that I think will make for easier calculations. Here's my final notes.

Earth work: 1 man working day per 10 cu. feet.
All trenching deeper then 10 feet and all tunneling requires wooden shoring- add half of total calculation to time estimate.

Timber construction: 2 man working days per 10 sq. feet.

Stone construction: 8 man working days per sq. foot (of 5 ft. thickness) for structure up to 50 ft. high.
Walls of greater thickness can be figured in multiples of 5 feet by doubling or tripling calculation. If castles walls are of inner and outer walls filled between with rubble, calculate fill area up to 5 feet thickness at half time requirements. This would apply to earth and rubble filled wooden walls/ramparts as well.
Walls taller then 50 feet must be thicker then 5 feet.
Additional time costs required for scaffolding, ramps, and craning:
-double time for structures over 60 ft. high.
-triple time over 100 ft. high.

Road construction on clear land:
-1/2 man working day per 10 sq. ft. of dirt road.
-5 man working days per 10 sq. ft. of hard packed stone lined road.

General:
For time calculations, all resources are presumed to be readily available (within one 6 mile hex from building site). Otherwise, transportation times must be accounted for.

When calculating labor costs and time, you must have 1 man (support staff) for every 5 stone workers for quarry work and 1 man for every 10 wood workers for timber cutting.

You must also have 1 working animal (ox, mule, horse, etc.) for every 5 support staff, when resources are located outside of the castles immediate hex. For transportation of resources, you must have a cart or wagon for every pair of animals. This additional labor is not used in estimating time to complete project. Without them, the project is considered at a standstill.

You must have one smith for every 50 workers and/or every 4 working animals.

When calculating the square footage of castle walls, do not subtract for areas where gates and windows will be placed. Consider it solid wall for figuring time since these items require as much time to add.

One engineer overseer is required for project and one master tradesman is required for every 100 workers.


Now I'm ready to consider siege rules. I've been looking at Chainmail and adding some additional rules for burning wooden structures and figuring structural damage point values. But, I'm also considering using Delta's Book of War rules. Unfortunately, he does not include any siege rules, or maybe I should say that they are very scant. I may have to request that he work on that