*Victorian Buildings

Question 1

When was the Victorian Period

Answer 1

1837 to 1901.

Question 2

What features define a Victorian building?

Answer 2

Pointy buildings with steep roofs – battle of the styles gothic style prevails

Ornate features such as corbelling, decorated fascia boards

Timber window panes were larger 6 x 4 panes

Ground floor bay window often had its own roof.

Stained glass became in use generally above doors and at tops of windows.

Question 3

Can you list some typical defects which occur in Victorian buildings?

Answer 3

Nail sickness to roof slates

Spalled brickwork

Lack of restraint to flank walls.

Rotten floor joists and dry rot to ground floors caused by poor ventilation

Deterioration of filler joisted concrete slabs.

Question 4

What is nail sickness?

What causes nail sickness?

Answer 4

Numerous slates progressively slipping out of place due to failure of the poor quality galvanised or iron nails.

The nails holding the slates in position corrode due to exposure to the elements resulting in a slip of the slate.

Question 5

What would you recommend to address a roof suffering from nail sickness?

Answer 5

Isolated repairs in minor incidents - Refix the slates using aluminium or copper fixing.

Replace all of the slates if more than 15% of the roof is suffering from nail sickness.

Question 6

What is spalled brickwork and where might you expect to find examples of it?

Answer 6

Spalled brickwork is disintegration of sections of brick.

Often seen on exposed elevations such as parapets, close to the ground and near water runoff points.

Question 7

What are the causes of spalled brickwork?

Answer 7

Frost attack then takes place which requires regular freeze and thaw cycles when the material is wet. The expansion caused by the freezing of the trapped water causes the brick to break/spall off.

Question 8

How would you remedy sections of spalled brickwork?

Answer 8

Remove the source of wetting. I.e. Repair leaking rainwater goods, etc.

Cut out and replace the defective sections of brick in isolated locations.

Question 9

What are the symptoms of a lack of restraint to flank walls and what other term is this defect referred to as?

Answer 9

The ‘book end’ effect.

Leaning flank and party walls

Vertical cracks in the front and rear elevations

Gaps appearing between floor and party walls.

Question 10

What are the causes of the bookend effect?

Answer 10

Lack of movement joints in terraces.

Contraction tears walls at window openings

Brick fragments fall into the cracks and prevent closure on expansion

After cyclical movement, the flank and party walls are pushed furthest away so that they are out of plumb.

Question 11

Why are expansion joints needed in long sections of brickwork?

Answer 11

Expansion joints allow thermal and moisture movement to take place (expansion and contraction).

Question 12

What would you recommend to address Victorian buildings suffering from the book end effect?

Answer 12

Cut movement joints into long sections of brickwork terrace walls at 12 -15m centres.

Undertake repairs to the cracks, windows, etc as required.

Question 13

What are the symptoms of rot to timber ground floors?

Answer 13

The timber floor joists become dry and crumbly, lightweight with a light brown colour.

Deep cuboidal cracking appears on the timber.

Mycelium appears along with a musty smell and yellow staining to the timber.

Spores appear like a fine layer of red rust over the timber and substructure brickwork.

The fruiting body is pancake shaped with a white margin.

Question 14

What are the causes of dry rot to timber ground floors?

Answer 14

Timber which has a moisture content between 17 – 22% is susceptible to dry rot.

Blocked air vents and no DPC present are the most common causes.

Question 15

How would you remedy an outbreak of dry rot in a Victorian property?

Answer 15

Eliminate the source of the moisture and promote rapid drying

Remove all of the rotten wood and up to 450mm of sound, adjacent wood.

Treat all surrounding timber and brickwork with a preservative.

Splice in and install new, treated timbers and coat with preservative.

Improve the ventilation pathways if possible.

Question 16

What are the symptoms and causes of wet rot?

What are the causes of wet rot?

Answer 16

Dark brown colour to the timber.

Very damp conditions.

Cracks run longitudinally across the grain.

Fruiting bodies rarely found inside the building.

The causes are very damp conditions, over 25% moisture content in timber and continually moist conditions, e.g. faulty plumbing.

Question 17

How would you remedy timber suffering from wet rot?

Answer 17

Isolate the affected timber from the source of moisture.

Cut out the old, rot affected sections of timber and splice in new timber.

Use a moisture meter to ensure that the full extent of the rot has been removed.

Question 18

Can you describe the typical rot lifecycles?

Answer 18

1. Spores are released from a fruiting body
2. The spores develop into Hyphea which penetrate the wood
3. A mass of hyphea gathers to form mycelium
4. The mycelium form together to create a fruiting body.

Question 19

What are filler joisted concrete slabs and what are the signs of its deterioration?

Answer 19

Clinker concrete was used in the Victorian period

Straight cracks in soffits at regular intervals across the ceiling indicate steel filler joists.

Question 20

What is the cause of the deterioration?

Answer 20

When clinker concrete is wetted, it draws out acids from the incumbent coal in the clinker concrete which corrode the steel filler joists.

Steel expands when corroded and the expansion pushes concrete cover off and forces the slabs apart.

Question 21

How would you address the deterioration of filler joisted concrete slabs?

Answer 21

Replace any corroded sections, or the entire beam if necessary, and make good.

All water ingress should be stopped and the expanded steel treated to prevent further corrosion with a Sika Product.

Question 22

Can you draw the deterioration of joists?

Question 23

What defects are common to both Georgian and Victorian Buildings

Answer 23

Sulphate attack of mortar.

Partially removed chimney breasts.

Rotten joist ends.

Question 24

How would you identify if sulphate attack had occurred in mortar?

Answer 24

Bulging walls.

Distorted chimney stacks.

Cracked or loose mortar.

Friable (easily crumbled) mortar joints and loss of bond.

Question 25

Can you tell me what causes sulphate attack in superstructure and substructure?

Answer 25

In superstructure brickwork, driving rain or moisture which has become trapped in render, saturates clay bricks and transports soluble sulphates from brick to mortar. Requires saturation over an extended period.

In substructure brickwork, sulphates can form from ground water movement and through capillary action, enter the brickwork and cause damage by expansion of the mortar and distortion of the wall.

Question 26

How would you remedy sulphate attack?

Answer 26

Eliminate the source of water and replace the affected bricks

Where the wall cannot be prevented from being wetter, say an elevation, and the bricks have a high sulphate content, demolish the wall and rebuild with sulphate resisting bricks and mortar.