How do I check an old extension conforms to building regs?

We have just received our homebuyer report on the period property we want to buy.

It has pointed out that some aspects of the loft conversion and rear extension might not conform to current building regulations.

But both of these were done more than 20 years ago by previous owners, so there are no certificates.

A surveyor’s job is to inspect the property’s condition so that the buyer can move into their new home aware of any potential issues

A relative who is a chartered surveyor has read the report for us and highlighted three potential problems:

1. On the rear extension, you need to be sure that the walls are of standard 225mm thickness if solid, or 275mm if they are cavity walls.

2. Does the loft have a floor that is independent of the bedroom ceiling joists? The concern here is whether the roof remains properly supported.

3. The vendor has no electrical test certificate, which is a concern as rewiring is very disruptive and costly.

Do we need to get a structural survey? That seems like overkill to us.

And is it the seller’s responsibility to provide an electrical certificate before we proceed, or ours to get an electrician to go in and check out the property? 

Are there any other considerations? Via email

Ed Magnus for This is Money replies: Building regulations set standards for the design and construction of buildings to ensure safety for those living within.

Homeowners are legally responsible for ensuring that all structural work, including loft conversions and extensions, complies with current building standards, and for obtaining a completion certificate to prove this.

Building regulations are constantly evolving, and it is likely that construction carried out over twenty years ago would not meet the standards of today.

But any buyer would wish to know that such major works at the very least adhered to the building regulations of the time.

Not having the required certificates does not mean these works did not adhere to the standards of the time – just that official approval was not obtained.

The homebuyer report is a less costly and less intrusive alternative to a structural survey, otherwise known as a building survey.

The structural survey typically involves the surveyor checking behind walls, looking between floorboards and above ceilings as well as giving advice on repairs.

This is Money spoke with a buying agent, a surveyor, an estate agent, a solicitor, a mortgage advisor and an architect to help provide some answers.

Is a structural survey overkill?

Nigel Bishop, buying agent at Recoco Property Search replies: For older homes, a homebuyers report can be a waste of money.

It’s fine for a modern apartment built within the past 10 years if you’re seeking some peace of mind, but if you’re buying a period property then you should arrange for a qualified surveyor to carry out a full structural survey.

The cost of a structural survey typically varies between £500-£2000 depending on the property.

This may seem expensive compared to the homebuyers report, but if you buy a property and find there is a major structural problem that ends up costing you £50,000, you’ll regret choosing the latter.

A structural survey enables a buyer to fully understand the property they are buying. 

If there are issues, it will allow them to make an informed decision over whether to walk away or renegotiate the purchase price.

You will need clear-cut written evidence in order to renegotiate, and a structural survey should provide that.

What would a surveyor advise?

Grant Barnes, a chartered surveyor at Barnes and Barnes surveyors replies: I would say that if the property has been structurally altered, then a building survey would be most appropriate.

This would examine whether the walls are solid or cavity insulated, and whether the floor to the roof conversion is structurally adequate.

The buyer should also seek confirmation of building regulation approval for the roof conversion and any structural work.

But if there is any doubt, then further investigations should be requested from a chartered building surveyor or structural engineer.

Who’s responsibility is the electrical test certificate?

Jeremy Leaf, north London estate agent and a former RICS residential chairman replies: With the electrical test certificate, there is no legal requirement when selling a property to provide one – unlike with rental property. 

It is up to the buyer to enquire about a property's electrical safety

It is up to the buyer to enquire about a property’s electrical safety

However, it is paramount that you make sure the electrics are safe and up to standard.

A buyer might argue that the seller ought to provide the electrics in good working order at the time of sale.

On the other hand, the seller may say they are happy with the electrics and if the buyer wants any tests carried out, they must pay themselves.

The fairest solution may be to split the costs or renegotiate the asking price to reflect any work required. At the very least, an inspection prior to signing on the dotted line is wise.

What about the legal advice?

Rob McKellar, senior practice director at Slater and Gordon replies: The limitation period on building regulations is one year, which means a local authority can only enforce remedial works within 12 months of building work completing.

However, the local authority can still enforce remedial action outside this one-year period if the works are deemed to be dangerous.

What building regulations do not prove is whether something is safe or structurally adequate.

They only prove that the works were undertaken in line with the building regulations in force at the time.

If there is a concern over the safety of the extension or roof and the risk of future enforcement action, one option is to obtain building regulation indemnity insurance to cover the potential costs.

This should cover any potential costs in the future were the local authority to enforce remedial action.

Furthermore, if anybody contacts the council about the works then this will invalidate the indemnity insurance – so if you want to use the insurance option then you shouldn’t get the council involved.

Will it impact the mortgage application?

Jonathan Harris, managing director of mortgage broker Forensic Property Finance replies:

From a mortgage perspective, the issues raised may not have been picked up and flagged as part of the mortgage valuation.

A homebuyer report is a separate, more detailed, inspection carried out for the benefit of the buyer but not for the purposes of the lender.

So, while the matters will be of concern to the buyer, they may not impact the suitability of the property for a mortgage.

How can the buyer check the rear extension themselves?

Conrad Cherniavsky, an architect at CVC Architecture replies: The easiest place to determine the thickness of a wall is at window or door openings.

You should be able to get a tape measure through an open window and estimate how thick the walls are.

If this is not possible, the brickwork should be visible from the outside, so check the patterns of the brickwork. 

If it is laid as a ‘stretcher bond’ it will most likely be a cavity wall.

If the bricks have been laid in ‘Flemish bond’ it is most likely a solid wall.  

A Flemish bond (left) is formed by laying header (laid width-wise) and stretcher (laid lengthwise) bricks alternately in each course. Stretcher bond (right) is the most commonly used bond in the UK and is a pattern made only using stretchers

A combination of a visual inspection and measuring the thickness should allow you to determine the construction.

You can also make an assessment by inspecting the area where the new extension meets the old house – both inside and outside – to see if any cracks have formed as a result of ground movement.

Some small hairline cracks are normal, especially if the extension is 20 years old, but any larger cracks would indicate that the extension is not very well supported.

How can they check the roof is properly supported?

Cherniavsky adds: The loft roof should be supported by itself and not by the floor structure, but both are important structural aspects.

The buyer should be able to measure the thickness of the floor where the staircase cuts through the floor structure.

It should be at least 200mm thick which would indicate it is compliant.

Concrete or clay roof tiles can add too much weight to an old roof, resulting in sagging

Concrete or clay roof tiles can add too much weight to an old roof, resulting in sagging

Another test, albeit slightly rudimentary, is to simply jump up and down on the floor.

If the floor bounces and creates significant vibrations in the room, it is a sign that the floor is not properly supported.

Bear in mind that it is normal for a bit of bounce in timber floors.

Regarding the loft roof, you can quite often see if a roof is starting to sag – so try and make a visual inspection.  

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