Older walls were built of anything that came to hand; bricks, tiles, stones or even pebbles.  Attempts to create reproductions of old walls often fall far short of the mark, and it's hard to explain why.  Maybe the gaps are too big these days. 

Cracks

Old farmhouses often have some horrendous looking cracks in the walls and it is difficult to know how serious they are.  They will all look serious to the untrained eye!  Whitewashed walls make cracks very visible.  Unless you paint the walls black you will need to fix them!  They can be caused by several things including subsidence, stress, poor foundations, earthquake, or simply weak building materials.  You will often find fine cracks where plaster has dried out.

 

These are the least worry, although some can be very serious. The ones that start at roof level and fade out before the reach the floor are usually due to a slight spreading of the walls on either side caused by the weight of the roof on walls constructed of old, weak mortar.  When a roof is restored then a seismic ring of reinforced concrete or iron channel is put into the top of the wall around the house.  This usually prevents any further movement.  If the roof is not being restored then it will be necessary to put a tie rod through the house with a plate on each end, a very common solution.  The rod is heated up, the nuts or wedges are tightened and as the rod cools and contracts it pulls the walls back together.

 

If the parts of the wall to either side of the crack are at different levels then subsidence is the problem and the foundations will need to be reinforced.  This is usually done by micropiling or putting a ring of reinforced concrete right around the house at ground level.  

 

These are a bit more of a worry.  Either the wall above the crack has gone up, or the wall below the crack has gone down.  The first is pretty well impossible - so something has sunk.  At ground level this is usually due to the foundations and work will need to be done as mentioned above.  Sometimes the crack can be found at first floor level and it could be due to a lightweight dividing wall being added on a floor where there is no wall below, just a large beam.  The beam may spring a little taking the wall with it and leaving a hairline crack.  Nothing much to worry about here and the only real cure is to add a little more rigidity to the beam below, or remove the wall. 

 

This type are more complex.  If they run upwards towards a corner with a similar crack on the adjacent wall then, again, foundations are the problem.  The corner of the house will need strengthening.  A series of almost vertical cracks will probably indicate earthquake damage.  Often there will be no further movement and it may be a matter of simply filling in the cracks with a strong bonding material.

 

Finally we must stress that these are only guidance notes and you should always get the opinion of an expert.  We have several who can advise you including architects, geometras, geologists and building engineers.

 

Putting tie rods through a building will help to consolidate it.  We have rods through our house in both directions and they certainly give me peace of mind, if nothing else.  Ideally they are buried in the walls or floors but I have seen some exposed ones, painted dark grey, and looking quite attractive.  If inserted in the walls a channel is cut using an angle grinder, a hole is drilled out through the wall and the rod inserted.  It is heated up and the nuts or wedges are tightened.  Then as the rod cools it contracts pulling the walls together.  The channel is then filled and the wall made good.  The problem with this method is that you are weakening an already dodgy wall and the plates on the outside are close to the corner.  It is better to sink them into the floor when restoring the house if you can.  They can sit in the reinforced concrete alongside the pipes for heating and cables.  There are a wide variety of plates, crosses and strips used to spread the load on the outside of the wall and sometimes these are quite attractive, adding to the overall character of the building.

Finishing

We have seen some amazing works of art decorating the walls of old buildings.  It is quite common to see restored houses with intricately painted walls too but the cost is high for a really good job.

New walls

The modern method of building walls is to construct vertical columns of reinforced concrete and infill with extruded bricks.  This is cheap, strong, and provides good insulation.  The extruded bricks are easy to break into when installing pipes for plumbing and electricity.

 

This page will be added to as time goes on but if you wish to contribute please contact graham@laportaverde.com