Category Archives: Kitchen Building

Boiling coppers

I think that extant boiling coppers and rocket stoves have a lot in common.  Here’s the description of how boiling coppers/furnaces work from “Cooking and Dining in Medieval England” by Peter Brears (p155, 156):

line drawing showing furnace at Caernarfon Castle
Caernarfon Castle boiling furnace 1294 – c.1301 (from p.157 Cooking and Dining in Medieval England)

The actual furnaces have an almost hourglass section, the bottom half containing the burning logs and faggots in its combustion chamber. The flames were then constricted, to emerge as a strong, vertical blast directly under the convex base of the boiler mounted above, the bowl shaped upper section of the furnace keeping the flames just a few inches from the boiler’s sides, before the passed up the flue.


p.157 Cooking and Dining in Medieval England
Ashby de la Zouch boiling furnace 1474-83 (from p.157 Cooking and Dining in Medieval England)

The surviving furnaces at Warkworth, Ashby de la Zouch and a number other castles all adopt a common form, having a cylindrical interior with a ledge some 30 inches from ground level, an arched fireplace facing into the side of the adjacent hearth, and an enclosed space above, with a vent leading either to the open air or to the upper part of the main chimney.

Once a large pot and been suspended inside, and its rim sealed to the inner ledge with mortar and sheet lead, this type of furnace could be fired like a bread oven, burning faggots being thrust to the back of its firing chamber, so that the flames would pass beneath and around the pot, before emerging from the top of the fireplace arch and ascending the main chimney.  This ensured that as much of their heat as possible was transferred to the pot, rather than being lost to the open air.


Hampton Court Palace Boiler
Hampton Court Palace Boiler 1529 (from “The Taste of the Fire” p32)

In a later development, the fireplace was still located in the side-wall of the hearth, but the flames were now conducted backwards under the bottom of the boiler, around a baffle, and then forwards around both the upper sides of the boiler to a chimney directly above the fireplace.  This made for a much more efficient use of fuel, since the flame passed twice their former distance around the boiler.  This system was later used for most great boiling houses, including those at Hampton Court Palace.

The other place to work out period water heating technology is in brewing;


Boiling house and rocket stoves

One of the other things I am still working out how to include in the kitchen hearth is a boiling copper.

The Hampton Court kitchen has a boiling copper;

Meat stock and boiled meat were produced in the boiling house in a great boiling-copper which had a capacity of about 75 gallons. – link

boiling copper and oven

There’s also a boiling copper in the Tudor kitchen at Winkhurst, part of the Weald and Downland museum.

I can’t see where the chimney is but with only a minor modification I reckon that it would be straightforward to build a rocket stove below the pot, making a very fuel efficient, low smoke fire – just what you want when you’re keeping under the radar of the CFA.

It should also be pretty easy to make one for at Festival too.

It should also be pretty easy to incorporate a rocket stove and make a stove top like the ones at Hampton Court;

hampton court kitchen stoves


Here are my rocket stove links;

10 Principles of rocket stove design

Manual for rocket stoves.  Includes suggested dimensions of chamber and links to good slideshows of construction.

Manual for building an adobe rocket stove with a skirt to insert a pot

Youtube video showing the adobe technique – easy to watch

Second youtube using the rocket stove to heat a cob oven

Youtube showing internal details and long term usage issues when using the classic tin cans to build a rocket stove and oven.

Building a rocket stove with 24 bricks
this is the one that would be great to make at Festival and I might have a go at in the backyard too.


I just found this great listing of Fireplace design in a bunch of houses at the Weald and Downland museum.

Poplar cottage inglenook design

It includes a description of the Poplar Cottage inglenook, which I used as a basis for the kitchen.

Unfortunately, it includes the following;

We are not certain how the smoke escaped at the top: we have reconstructed the gable with a small triangle open at the top, but it is possible that there was a structure like the top of a chimney to allow the smoke to escape vertically.

Also, I wish I’d worked out how to include an oven in the design of the hearth, like the 15th C House from Walderton

Roof options – slate or sandstone?


Sandstone appears to be a roofing material used mainly for castles and churches.


Lots of floor tiles are available second hand.  They tend to be much thicker than the commercial roof tiles.  We wondered what thickness traditional roof slates are:

I found these two articles on english restoration of slate roofs.

the second suggests that english slates are traditionally 5mm or so.  OTOH, the thicker the slate, the stronger the tiles are.

This article is about the excavation of a medieval hospital in sussex –  They found stone fragments that appear to be roof tiles and have “thickness varying between 6 and 11mm”
This article is about the slate industry and in 1923 2nd quality slates were “3/8 inch or more thick”. (9mm)

Great video of slate roofing – it looks like we can avoid drilling into slates if we use the hook fixing method – a european method.  Of course, then we we need to work out how to organise hooks suitable for tiles “10-15mm” thick.





The roof structure

I’ve really struggled with the roof design.  We built the main structure and then had to work out how to attach the tiles. While we worked that out we decided to add a timber paneling ceiling.  This means we can hide some modern insulation in the roof.

The books I have don’t really talk about how to attach a roof covering.  We were planning to use commercial roof tiles until we made our own ceramic tiles, so we need to hang the tiles on battens.  I needed to know how the battens were attached to the structure when they were perpendicular to the purlins and what supported that skinny wood when the roof trusses were 1m apart?  Work paused while I did other things and let my back brain sort it out.  The kitchen frame looks like this;

Then I worked it out – we need a roof structure, in addition to the main structure.  In the photo below, you can see the main frames and the large purlins stopping the frame from racking.  On top of the purlins are “common” rafters with the battens on top of that.  Diagrams of timber frames typically don’t show the roof structure, so I’ve had to look at photos like this one instead.

Siddington Barn, Gloucester. 1245-47

Next week, we’ll add the insulation,  new rafters and battens.  Just as soon as we work out what roofing material we’re using, so we know the batten spacing to use.  I see a lot of birdsmouth joints in my future.

Unless we do this instead;


Lovely presentation of roof frame types and their dendrodates.

The Kitchen Building – Background

This post will introduce you to this “ridiculous project” and provide a place for me to document the sources and process we’ve used to make the kitchen building.

What is it?
It’s a kitchen building.  It was originally conceived as a way to avoid local fire restrictions by putting a cooking fire inside a building.  It was also a way to improve our medieval cooking experience.  Also, big beams!

The beginning
The project started in February 2006.  After some discussion amongst friends we agreed that we wanted a permanent building at Crossroads Medieval Village to augment our Rowany Festival experience.  We started by agreeing that it would cost real money so we started a savings fund based on a small contribution each fortnight.  That fund has been used to pay for all the materials of the kitchen, as well as canvas for a pavilion and some funky cooking gear.  That building was going to be two bays and include a composting toilet.

A new location
Rowany Festival changed site in 2008, and we realised that our building would be pretty inaccessible to us over the rest of the year.  We had been part of a group of Stormholders who were involved in a camping event in January and decided that we should build a small building to house the cooking. I posted my first notes about the kitchen in 2008.

The photos here chronicle some of the work we’ve done on the kitchen.
October 2008 – start thinking about a design
September 2009 – dig foundation for wall – we hired a digger! slaked lime for mortar
December – concrete foundation poured, free tiles sourced and taken to site
January 2010 – timber purchased and joinery begun
February 2010 – more timber work
August 2010 – Thinking about bricks and mortar
September 2010 – revised hole and more concrete poured, brickwork commenced
October 2010 – more bricks and also woodwork
December/January 2011 – The big push.  Spent a fortnight camping onsite, brought in more people, transported the wood to site by truck and complete the main structure over 2 extra weekends. Changes required which may satisfy the CFA.
June 2011 – lining boards put on roof
May 2012 – After an extended break, wattle and daub walls started.