1940's & 1950's
1940's&1950's
Extensions to provide additional living spaces or bedrooms
Removal of internal walls to create open-plan living / dining / kitchen areas
Replacement or repair of original roofing or external cladding
Addition of insulation in the roof space or under the floor
Replacement of original windows with aluminium frames – may be single glazed
Replacement of original kitchen and bathroom fittings
WHAT YOU MIGHT FIND IN YOUR BUNGALOW –
AND WHAT CAN BE DONE...
FOUNDATIONS & FLOORS
Missing or inadequate piles, bearers and joists
Poor subfloor structures can result in:
· Sagging joists or bouncy floors
· Uneven floors
· Sagging verandahs and porches
Identify areas where foundation structures are causing problems and replace or support with new concrete piles and new bearers and joists
Previous renovations to piles, joists or bearers
The original concrete piles may have been replaced – however depending on how long ago this was done, these may have become compromised over time
Since 2011 most structural timbers must be treated to protect against insect attack and decay:
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Treated timbers are likely protected with CCA (copper, chromium and arsenic) – banned in most other countries but still used in NZ – or with boron (radiata pine – pink colour)
Handling and cutting treated timber must be done with proper protective equipment – gloves, mask, goggles, long sleeves to cover skin
Any sawdust or offcuts must be carefully disposed of to avoid soil contamination
Depending on your budget you may wish to choose timber treated with more natural products such as MCA (Micronised copper azole)
Joists and bearers may have rot or borer damage
The borer will likely be long gone but the holes remain, creating risk of moisture getting in to the timbers
Identify areas most affected and replace with new joists and bearers
No damp proofing membrane between concrete foundations and timber framing
Install damp proofing membrane layers when renewing piles, joists and bearers and when retrofitting underfloor insulation, to protect the flooring structures and insulation from moisture rising from the ground
This may be done from below but depending on access may be more easily done from above, removing the flooring to make the necessary repairs
Damp proofing sheets are heavy-duty polythene, must cover the entire ground area, and must be well secured to the foundation walls and piles – if your budget allows, get a qualified professional or builder to do this task – proper protective equipment should be worn (mask and gloves) to protect against breathing in dust or mould from rotted timbers
Damp proofing must be compliant with the Building Code E2 External Moisture and E3 Internal Moisture and with NZ Standard NZS 4246.2016:
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(guidance included)
Limited ground clearance, difficult access
If there is inadequate clearance between the joists and bearers and the ground, the best option is to tackle each room from the top – take out the flooring and address the subfloor structures from above before:
· Installing damp-proofing (plastic sealed closely to the subfloor structure to protect against moisture)
· Installing good insulation
Replacing or renewing the flooring
Rising damp
Install damp-proofing to protect against moisture
Improve ventilation in the subfloor space
Identify problem areas and replace piles or timbers as necessary
Cracking or deterioration of concrete or brick foundation walls
Identify problem areas and the causes – subsidence, earthquake damage, inadequate or compromised foundations
Restore level footings for piles and foundation walls, and repair and replaster as needed
Blocked or damaged ventilation grilles in foundation walls
Check ventilation grilles in the foundation walls are clear – if necessary you can create new ventilation grilles to improve airflow
Poor subfloor ventilation
Check ventilation grilles in the foundation walls are clear – if necessary you can create new ventilation grilles to improve airflow
Lack of underfloor insulation
Retrofit suitable insulation – this may be done from below if there is reasonable access, or if there is inadequate access to the subfloor area, you can go down from the top, removing the flooring to make necessary changes while you install damp proofing and insulation
Retrofitted insulation that is inadequate or deteriorated
Through the 1970s many homes were fitted with sisalation foil, intended as underfloor insulation – this was often installed with a “draped sag” between joists with small holes for drainage of any moisture, compromising any insulation effectiveness
Since 2016 it has been illegal to install or repair sisalation foil in residential buildings because of the risks of electrocution (under the Building Code Clause G9 Electricity) – sisalation foil itself is not illegal, but installation or repair is now banned:
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Removal should be done by a qualified professional with input from an electrician for basic safety
Replace with new effective insulation panels
FRAMING, INTERNAL WALLS & CEILINGS
Untreated timber framing and boards – may be either native timber or exotic
Assess the extent of damage and replace with new timber, plasterboard or other linings
While borer infestations will likely be long gone the holes remain and create significant risks for moisture getting in to the wall cavity or ceiling space
Depending on your budget, you may wish to choose timber and linings treated with more natural products such as CHECK WITH DAN
Plasterboard or hardboard linings – may have deteriorated
Replace with new plasterboard or other linings as needed – dispose of the old material safely as it may include asbestos
Waterproofing underlay / moisture proofing membrane – or inadequate old building paper layers
Building paper was generally installed behind wall cladding and roofing during the 1940s and 50s except in some (northern) areas. However the original building paper will likely have become compromised over time resulting in rot or deterioration of framing
Wall underlays must now be compliant with the Building Code E2 External Moisture; E3 Internal Moisture; B2 Durability; and C1-C6 Fire Protection:
BRANZ report:
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A range of modern flexible and rigid underlay options are designed to support the weathertightness of the building, separate external wall elements from internal elements (framing, insulation and linings), protect against water vapour, be fire resistant, restrict airflow and support insulation
There are two basic ways to retrofit underlay / moisture proofing – from the inside or from the outside – see Insulation below
No insulation in walls
There are two basic ways to address a lack of wall insulation:
From the inside – strip out the interior wall linings and retrofit:
– Moisture proofing membrane layer
– Insulation
– Optional service cavity – benefits include minimising thermal bridging
– Install new interior linings with airtightness sealing
From the outside – strip off the exterior cladding and retrofit:
– Insulation
– Moisture proofing membrane layer
– New exterior claddings
An alternative to avoid disruption or problems with the existing structures and linings is “outsulation” – putting on a thermally-efficient wrap system over the existing weatherboards or cladding – this can include additional framing, water resistant and air control layers, and insulation panels inside a new external cladding
Retrofitted insulation may include urea-formaldehyde foam
Problems include:
· Reduced thermal effectiveness due to shrinkage or gaps
· Moisture retention in the wall cavity
· Health concerns
· Fire hazard
· Environmental impacts
BRANZ study:
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Remove and replace with new insulation
Removal should be undertaken by qualified professionals using proper protective equipment and disposing of the material safely
Draughts and gaps – no airtightness
1940s and 50s homes are more sturdy than many earlier eras’ homes but will still be relatively draughty from loosening window structures and floors, and open chimneys
Identify problem areas:
· Window and door frames
· Skirtings and floors
· Chimneys
· Vents in ceilings
Seal properly with weather stripping around windows and doors, or sealant (silicon caulking) – if this has been done previously it may need renewing
Check window structures and hinges – retrofit with new double or triple glazed windows (PVC or thermally broken aluminium can be retrofitted into original timber window frames)
Install effective insulation
If replacing wall linings, skirtings or floors, seal the joins properly with tape or sealant
Walls no longer square or out of plumb
This may be a result of undersized structural timbers – rafters, framing, joists
Check foundations – piles, bearers and joists – and replace or repair any problem areas causing uneven levels
Renew wall linings as needed – rehang doors as needed
Dampness – mould on walls and ceilings in rooms with inadequate ventilation, rot, mustiness and smells
Check the underfloor space for moisture and ventilation
Clear ventilation grilles in the foundation walls or add new grilles to improve air flow
Install effective underfloor damp proof layers and insulation
Replace any rot-damaged timbers
Replace with new plasterboard or other linings as needed – dispose of the old material safely as it may include asbestos
Asbestos
The first check for any renovation is to assess for asbestos in the structure and materials – this must be done by a properly qualified professional
Removal and disposal of asbestos must be undertaken by a properly qualified professional
Lead paint
There will very likely be layers of old lead paint especially in kitchens, bathrooms and service areas – this may be covered over by later layers of other paint
Lead paint must be taken off using proper protective equipment – respirator mask, goggles and gloves – use a tarpaulin so it does not get into the ground and contaminate the soil
Do not dry sand the paint as this will create dangerous dust
Lead paint must be safely disposed of – check with your local council for regulations and collection for hazardous waste
Worksafe Guidelines:
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Rodent nests
Tackle these with extreme caution using proper protective equipment – mask and gloves – use a tarpaulin or strong bin bag and dispose of the nest and other material safely
CLADDING
No waterproofing layers, wall underlay or building membrane
See Waterproofing / underlay in FRAMING, INTERNAL WALLS AND CEILINGS above
Timber weatherboards – may have moisture, rot or borer damage
Assess the extent of damage and replace with new weatherboards or other cladding
Check around:
· Corners and joins
· Windows and door frames
·Bow and bay windows that extend beyond the main exterior walls
·Exposed areas, especially where vulnerable to wind driven rain or extreme sun exposure that would dry and shrink the timber
·Previous renovations that may have compromised the weathertightness of the building
While borer infestations will likely be long gone the holes remain and create significant risks for moisture getting in to the wall cavity or ceiling space
Depending on your budget, you may wish to choose timber and linings treated with more natural products such as CHECK WITH DAN
Asbestos-cement sheets or shingles – likely to be cracked or water damaged
The first check for any renovation is to assess for asbestos in the structure and materials – this must be done by a properly qualified professional
Removal and disposal of asbestos must be undertaken by a properly qualified professional
Brick – likely to be cracked or water damaged
Identify problem areas and check for subsidence, problems with the foundations, damp, lack of damp proofing, or other problems such as tree roots
Repair and replace as necessary
Remove brick chimneys down to the floor (concrete pad) level
Stucco – likely to be cracked or water damaged
Identify problem areas and issues with subsidence, foundations or wall framing, dampness or rot
Repair and replace as necessary
No insulation in walls
See Insulation in FRAMING, INTERNAL WALLS AND CEILINGS above
Lead paint
See Lead Paint in FRAMING, INTERNAL WALLS AND CEILINGS above
WINDOWS
Original timber framed windows – single glazed
Retrofit with new double or triple glazed windows (PVC or thermally broken aluminium can be retrofitted into original timber window frames)
Timber frames give a significant advantage in terms of thermal efficiency – however it does require maintenance and making sure the weatherproofing is in good condition
Recess the new retrofit windows within the wall to align with the line of the insulation – to avoid heat loss and significantly improve the thermal efficiency of the home
Lead paint on sashes and frames
There will very likely be layers of old lead paint especially in kitchens, bathrooms and service areas – this may be covered over by later layers of other paint
See Lead Paint in FRAMING, INTERNAL WALLS AND CEILINGS above
Inadequate, damaged or corroded sealing and flashings
Identify any problem areas and replace
Check particularly around windows exposed to weather and wind driven rain, or located in damp corners or behind vegetation for dampness issues
Check for any damage to internal framing and linings from compromised window seals – water may travel some distance within the structure to find the lowest point where moisture damage may appear
Timber window frames deterioration and rot – windows warping and sticking
Check window structures and surrounds:
· Seal any gaps between the window frame and the walls to avoid draughts and heat loss
· Replace old compromised putty or other window seals
· Repair or replace any joinery that has suffered from dampness, rot, or warping
· Check for any subsidence or other structural damage affecting the window
Retrofitted windows that have compromised the framing or exterior cladding
Homes from the 1940s and 50s had relatively small windows and so may have had 1970s or 80s or more recent replacements which may be:
· Single glazed
· Non-thermally-broken aluminium frames
· Inconsistent with the period style of the home
Check any previously retrofitted windows and the surrounding framing and cladding for any leaks, gaps or deterioration
Replace with new double or triple glazed windows with timber, thermally broken aluminium or PVC frames
Repair and re-seal any damage to the framing or cladding
ROOFS AND PARAPET WALLS
Corrugated iron
Most 1940s and 50s homes will have already had some or all of the roof replaced by now, although this may have been undertaken in the 1960s, 70s or 80s and may be compromised
Check for any problem areas and any resulting damage to the roof structure, ceilings or internal structures below
Replace with new long run steel roofing or other roofing (tiles, shingles)
Asbestos cement sheeting or shingles – may be cracked or corroded, or have moss or lichen spreading across
The first check for any renovation is to assess for asbestos in the structure and materials – this must be done by a properly qualified professional
Removal and disposal of asbestos must be undertaken by a properly qualified professional
Tiles – may be cracked or corroded
Tiles that are damaged or cracked are a major vulnerability for weathertightness
Check tiles carefully and replace damaged areas or if your budget allows, replace the whole roof
Inadequate insulation or retrofitted insulation that has deteriorated
Many 1940s and 50s homes will have had some insulation installed from the 1970s onwards, but by now this will likely be inadequate for today’s energy efficiency standards
Check any previous retrofitted insulation – replace with new properly efficient insulation
Make sure that the insulation is far enough away from the roofing structure to avoid condensation
Install effective moisture proofing layers to protect the insulation from damage
Deteriorated roofing underlay
Building paper was generally installed behind wall cladding and roofing during the 1940s and 50s except in some (northern) areas. However the original building paper will likely have become compromised over time resulting in rot or deterioration of framing
Roofing underlay is now required under the Building Code E2 External moisture (with a few exceptions):
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When upgrading insulation or undertaking any roof repair or replacement, install effective new underlay over the roof framing for:
· Protection against water getting in to the roof structure
· Absorbing condensation that forms on the underside of the roof
· Reducing air movement in the roof space
· Fire protection
Inadequate moisture control and condensation in ceiling space
The roof spaces in many 1940s and 50s houses had poor or no ventilation (except draughts and gaps, or gable end grilles or louvres)
This commonly results in the air in the roof cavity becoming laden with moisture – from the warmth and activity of people in the house below, or from leaks due to poor weathertightness
When temperatures fall, this moisture condenses on the underside of the roofing material, and can cause mould, rot, or otherwise compromise the timbers and any insulation material:
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Key factors are:
· Making sure that the insulation is far enough away from the roofing structure to avoid condensation
· Installing effective moisture proofing layers to protect the insulation from damage
· Reducing moisture in the air inside the home – with a proper balanced ventilation system, or other practical steps like ducted extractor fans in kitchens and bathrooms
Moisture damage or cracking to cladding under eaves
Check the soffits – the panelling underneath the overhanging section of the roof eaves – for deterioration due to wind-driven rain or other damage – this can be a point of vulnerability for moisture to get in to the roof space
Replace with new soffit panels as necessary
Lead flashings and lead-head nails
Lead flashings and lead-head nails were commonly used, but can likely result in problems with rust or the nails popping up as the roof framing timbers dry over time
This creates weathertightness issues and water getting in to the roof space – as well as releasing lead into the environment
Check your roofing carefully for missing or compromised nails – replace with galvanised nails or screws
Check for any lead nail remnants in the guttering and dispose of these properly – check with your local council for regulations and collection for hazardous waste
VENTILATION
No ventilation system
The only ventilation in 1940s and 50s era homes was from the draughts, from opening windows, and via the open fireplaces
If you are investing in improving the insulation, airtightness and internal moisture control of your vintage bungalow, you should consider installing a proper balanced ventilation system with heat recovery – to remove moisture and stale air, and bring in fresh air – heat is transferred from the stale inside air to the incoming air, to help maintain a consistent indoor temperature as well as manage any dampness issues
Stuffy interiors – smells and mould
Some rooms in older houses may have mustiness, mould or mildew, particularly:
· Bathrooms, kitchens or lean-tos at the rear of the villa
· In houses in shady gullies with little natural sunlight
· If leaks or moisture has compromised the cladding, framing or internal linings causing rot
· After flooding
Mould can be a major health hazard and can cause allergic reactions, respiratory problems, asthma, eye irritations, sore throats and skin rashes – some moulds produce toxic compounds, such as Stachybotrys (a greenish black mould that grows on timber, fibreboard, wallpaper and other materials
Mould must be dealt with properly to ensure the safety and wellbeing of people living in the home:
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If you suspect toxic mould, you should use proper protective equipment (mask or respirator, gloves, protective clothing to cover your skin) to take a sample for testing – if it is contaminated with toxic mould it should be removed by a qualified professional
You may have to remove and replace ceiling panels, wall linings, carpets or other contaminated materials, which should be properly disposed of
For lesser areas of mould, use protective gloves and mask – clean with bleach solution or other mould-removal products, and make sure the area dries completely afterwards – dispose of the cleaning materials carefully
Key factors to prevent mould recurring include:
· Ventilation and good airflow
· Insulation
· Removing and replacing any rotted timbers or linings
· Minimising internal moisture
REFERENCE LINKS
Building Consents
Structural building – additions, alterations, re-piling and foundation work, and some demolitions
Complete or substantial replacement of a specified system
Replacing exterior wall cladding that has failed within 15 years of installation resulting in damage to the wall framing
Demolition of an internal masonry chimney that is load-bearing (supporting roof rafters and ceiling joists)
Plumbing and drainage where an additional sanitary fixture is created
Installing a woodburner or air-conditioning system
Decks more than 1.5 metres above ground level
Consent Exemptions
General repair, maintenance and replacement of a component or assembly of the building using a comparable component or assembly in the same position – UNLESS it has failed to comply with the Building Code requirements for durability such as external moisture problems with wall claddings
Replacing metal roof cladding (IF it has lasted more than 15 years to meet Building Code durability requirements)
Replacing an old clay tile roof with a metal roof in the same position
Replacing old rotten wooden piles with new treated timber piles in the same positions, UNLESS the work is a complete or substantial replacement
Replacing doors and windows with new aluminium doors and windows in the same position
Repair or replacement of damaged masonry veneer wall cladding
Removal of a building element from a building that is not more than 3 storeys, PROVIDED THAT the removal does not affect the primary structure of the building, any specified system, or any fire separation:
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Removing a brick chimney on an external wall
Primary structure: walls, foundations, floors and roofs
Weathertightness
Fire safety systems
Full contact details
Address or location description of the site
Expected start and completion dates, and how possible delays will be dealt with
Contract prices and the payment process
Description of the building work including materials and products to be used (if known)
Which party is responsible for obtaining building consents and other approvals required
Who will be carrying out and/or supervising the workRemoving a brick chimney on an external wall
How defects will be remedied
How variations will be agreed before work continues
Dispute resolution process
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