Building a house in Amsterdam

The foundation

Before a house could be built it was necessary to mark the location of the foundations: "the setting out". To locate their correct position, the builders used planks and painted the intended thickness of the walls onto the planks. Then the trenches were dug for the foundation. The weight of the house had to be evenly distributed over the ground area otherwise construction faults could occur through subsidence. This is particularly the case in Amsterdam because of the high level of the ground water and the peaty soil. The solution was to drive long piles into the ground until they reached the sandplates at a depth of 40 to 60 feet. This was achieved by manpower.

For the foundation of the wall pairs of piles were driven into the ground 80 cm apart, until the length of the house was completed.

The tops of the piles were sawn level, and fastened together by nailing heavy wooden planks on top of them with iron or wooden nails.

The wooden foundation had to be kept submerged beneath the ground water level to stop the rotting process setting in, and thus avoiding subsidence.

Illustration from:
"De Beijekorf des Gemoeds"
Jan Luijken (1709)

The brickwork

The wooden foundation formed the base for the brick foundation. A brick wedge-shaped structure of about five layers was built on top of the foundation planks; the base being broader than the top. Three kinds of mortar were used. The layers in the "wedge" had a loam mixture between them. The brickwork above the wedge had a chalk or lime mortar, and a hard mortar, consisting of sand, chalk and trass was used in the five or six layers above and below ground level. A harder brick was used here forming a damp course to stop the ground water seeping up into the house causing rising damp.

The bricklayer ensured the bricks were laid horizontally and at right angles by using a tape attached to stakes, with measurements marked for the height of each layer and a plummet.

The carpentry

Only after the bricklayer had completed the cellar walls could the carpenter start to work on the cellar ceiling. The pine beams were anchored into the wall. A temporary work floor was placed on top of the floor beams so that the bricklayer could continue building the sidewalls until he reached the correct height for the next floor.

This process was repeated until the right number of floors had been completed.

The ends of the beams were sealed with tar to stop them rotting. The wall anchors kept the beams securely attached in the wall and also stopped the wall from buckling.

The roof

Only after the appropriate number of floors had been achieved and the parapet was at the right height could the carpenter start on the roof. The roof structure had to be extremely sturdy. This was achieved by using a system of triangles called trusses. A truss consists of a post and beam construction.

A curved brace was placed between the post and the collar beam to stop the structure from swaying. The beams were attached together by using a mortise and tenon fastening with wooden pegs of approximately an inch thickness.

Then the roof trusses were placed in the correct position and attached to the garret beams. The apex had to be placed before the rafters, tilelathes and tiles could be fitted. Finally the roof tiles were laid and were sealed on the inside with a mortar made from sand, chalk, and pigs' or horsehair. A hoisting beam was attached to two extra collar beams at the front of the house to raise and lower goods and furniture. Lead coated gutters and drainpipes were placed at an angle leading off to the back of the house to catch the rainwater.

Building the front and back facade

The front and back facades were completed last. Scaffolding was placed at the front and the back of the house. The bricklayer and the carpenter had to work together to mark out the location of the doors and windows. The carpenter then made the frames for the doors and windows, so the bricklayer could complete the facades. Meanwhile, the carpenter could make the windows and doors.

The facades were built at an angle leaning slightly forward to keep the rain off. The old wooden houses were also built in this way. The top floors protruded more than the bottom ones so that the rain ran off the facade without soaking it.

Brick houses were also made waterproof by filling the joins between the bricks with a high quality mortar that was water resistant.

The decorations

A decorative gable was placed at the top of the facade for the finishing touch. The stonemason made a specially carved sandstone frontispiece and shoulder pieces.

These elements were painted a creamy colour called "Bentheim yellow" because sandstone has the tendency to turn black.

links

Special thanks to the Amsterdam Bureau of Monuments and Archeology website, http://www.bma.amsterdam.nl

www.essential-architecture.com