Stone Tenement Structure

Your building has a supporting skeleton of walls, joists, beams and lintels which keep it standing. Any repairs required to this structure are important and need to be dealt with quickly. Alterations to the structure will require building control consent and consultation with other owners.

Main parts of the structure

This diagram shows the main parts of the structure.

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External walls

Up to 600 mm (2 ft) thick stone with a lath and plaster lining, these walls support the timber joists that run between front and back of the building.  Openings in the walls are supported by beams, lintels and bressumers, often made of timber.

External walls may be described as being solid but they are made of two leaves, an inner and outer, with the space between filled with smaller stones and lime. Large bonding stones laid at regular intervals tie the two leaves together.

You need to keep walls dry in order to prevent rot occurring in the joist and lintel ends which are embedded in the walls. This is especially important where walls were built more thinly such as around bay and oriel windows.

Internal walls

Generally made of 150 mm (6" ) brick, these walls will be load bearing if they support

Walls that run parallel to the front wall are almost always load bearing. Other walls that are not strictly 'load bearing'  may still be an important part of the tenement structure as they can brace and give strength to a load bearing wall.

Loadbearing walls should not be removed or altered without Building Warrant Consent and a structural engineers certificate. 

Altering and improving flats

Joists

Joists support the floor and tie the external walls together.  They sometimes also support internal walls.

"Dwangs" are timbers set at right angles between the joists to stiffen them.

Door frames

Door frames are often also structural, the "H" shaped frame tied in to the wall plate.  The brick opening over the door often contains a brick arch which helps support the wall above.

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Bed recess load bearing wall

Supports floor joists and stiffens structure

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Stiffening beam

Supporting joists at bed recess opening

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Structural Problems

Cracks

How to tell a structural crack from a decorative crack

Bulging Walls

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Some stone walls may not have been built vertically at the outset but are still quite solid. Bonding stones are usually built into the wall to tie the two faces of the wall together. Bulges can then occur because of

  • failure of these bonding stones
  • rot decay at the joist ends which weakens the stiffness of the structure.
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Bulging wallsJohn GilbertNot always this obvious, you may need to "sight" the bulge using a straight edge

Engineers may recommend monitoring of the wall if there are no other obvious defects. However bulges can be very dangerous and require the flats to be evacuated until the extent of the problem is known.

The problem can be expensive to deal with requiring walls to be shored up while floors are lifted to allow structural ties to be inserted.

Stair walls

These walls support the stairs.  Get structural engineer advice if you detect any bulges in the walls.

Professional help recommended?

If you have any concerns, call in professional help quickly.

Who pays?

These are normally common repairs.

Further information

Historic Scotland Inform Guide 'Foundations and Wall Footings'