Should I demolish my extension and rebuild?

Your property queries answered

Building extension: no waterproof membrane was laid and the damp is now risin. Photograph: Thinkstock

Q I hired a builder to build an extension for me, however he didn't lay a waterproof membrane on the floor and the breeze blocks he used were quite thin and there is no cavity. The damp is now rising. Is there any solution to this problem other than to knock down the extension and build it again from scratch? Any advice you can give me would be very much appreciated.

A The information provided doesn’t describe the location, overall scale/height of the work undertaken, or when it was carried out, in order to determine the full extent to which it comes under the relevant scope of the planning and building control regulations, nor does it indicate if the requirements for a valid commencement notice, if applicable, were met.

A competent designer and builder should have been engaged from the outset and the situation described raises serious doubts about this. Regardless of these statutory requirements, extensions, for example those encompassing habitable rooms, are also subject to the requirements of building regulations and the query posed, raises serious concerns in several areas.

Your account also strongly suggests a breach of building regulations and, if built in the last five years, or indeed a longer period where significant health and safety contraventions arise, they could attract enforcement procedures by the local authority resulting in likely demolition.

READ MORE

Nowadays “breeze blocks” are extremely rare and invariably such lightweight load bearing walls are structurally inadequate for typical loads.

The compressive strength is likely to be about 3 to 4 N/mm2 representing half the strength of standard concrete blocks (at least 7N/mm2 is required by regulations). The structural integrity of a single slender blockwork leaf (eg 100mm laid on edge), whether standard blocks or lightweight, as described, is invariably unsound.

This suggests a contravention of part A- (building regulation structural requirements) and also part D (materials and workmanship). Further questions arise in relation to other technical performance requirements, eg the foundation width and adequacy and overall thermal insulation performance. There may be other areas of contravention.

Failure to provide an underfloor damp-proof membrane, often incorporating a radon barrier in high radon areas, is in breach of part C of the building regulations.

The dampness described is no surprise and, in addition to the rising dampness, such construction is also prone to rain penetration.

In the circumstances, subject to further investigation, knocking down the extension and rebuilding it from scratch is unfortunately likely to be necessary. It would be prudent to contact a competent construction professional such as a chartered (registered) building surveyor, chartered engineer or registered architect for advice before proceeding further and then engage a CIRI-registered builder.

Kevin Sheridan, chartered building surveyor and member of the Society of Chartered Surveyors Ireland, scsi.ie

Legitimate offers

Q We are in the process of purchasing our first home. How can I be assured that there are legitimate offers on the property as I have no way of knowing?

AThis is an issue of concern among some buyers. Purchasing a home whether a first home or not is a significant financial commitment and buyers, quite rightly, want to be assured that if they are to make a counter offer on a property, that the current offer(s) are legitimate.

If a property you are interested in is being sold by way of public auction, then all bids for the property are made publicly and you will be able to clearly determine the level of bids.

If, however, as is most likely the case, that you are considering purchasing a property which is being sold by way of private treaty, frankly there is no definitive way in which you can determine if all the offers for the property are legitimate or not. The estate agent will record all offers on file but they are not obliged to share the precise level of bids with other interested parties.

They may disclose if the bid is a cash offer or subject to finance/survey etc.

Ultimately, you have to rely on the information being provided to you by the selling agent as being truthful and correct.

All property prices are recorded on the property price register after the sale has closed. So this can be a useful way to review the prices of properties in areas you are interested in.

It can also be a useful check to see the selling price of a property which you may have been bidding on.

All estate agents and auctioneers are regulated by the Property Services Regulatory Authority and bound by a code of practice which states "that the auctioneer/estate agent acts in the best interest of the seller and with integrity and fairness with others".

Shoddy dealings with sellers or buyers is likely to lead to an official complaint to the PSRA and if substantiated could result in a substantial fine, loss of licence and/or a prison term.

The regulations contained within the Property Services (Regulation) Act 2011 established the Property Services Authority on a statutory basis on April 3rd, 2012.

This legislation is robust and is there to protect both sellers and buyers. In the event that you have a grievance, you can lodge a complaint with the PSRA which will investigate the matter.

Gerard O’Toole is a chartered valuation surveyor and a member of the Society of Chartered Surveyors Ireland, scsi.ie

Damp chimney

Q I have recently purchased a new house and I notice that the chimney block work between the roof and into the attic is damp. Is this normal? I don't see any dampness on the other chimney.

A You do not say where your property is or if it is in an exposed environment. Is it a detached, semi or a terraced dwelling? You refer to the other chimney being dry; does this infer that the chimneys are on party walls? Is the chimney above roof-level built in brickwork or plastered block? There are a number of questions that arise, but in any event I would not expect to see dampness on a chimney of a newly constructed dwelling.

What form does the dampness take and where is it located on the chimney? Imperfections in the roof-weathering details at lead flashings, soakers, aprons, back gutters, slate and roofing felt will provide a path for moisture to enter. Was a damp-proof tray installed across the chimney’s construction? Was the chimney exposed for any length of time during construction where the chimney structure may have become saturated and is currently drying out? If the chimney is on a shared party wall with a neighbour, then they may be experiencing a similar problem, which should entail a joint exercise to locate the source of dampness.

Has the dampness occurred since your occupation or do you think it was present when you took possession of the property? I would expect a qualified surveyor to notice dampness on a chimney when inspecting the attic space during a pre-purchase survey. If you commissioned a survey, then the surveyor may be able to assist you. Furthermore as the property is a new dwelling then it may well have been constructed under the new Building Control Regulations system (BCAR). Since March 2014, all new developments are subject to a more rigorous certification in lieu of the previous self- certification system. You may be able to check with your local council if there is documentation available and if so what level of detail was submitted which may help to identify the construction used.

A careful internal inspection of the attic, together with an external examination of the chimney and roof area with binoculars should highlight any imperfections.

Otherwise it may be necessary to organise access at roof level for a closer inspection.

I would recommend that you seek an opinion from an experienced chartered building surveyor to evaluate the cause and whether there is a problem with a neighbouring property where co-operation will be necessary. If remedial work is required they can advise accordingly.

James Drew is a chartered quantity surveyor and a member of the Society of Chartered Surveyors Ireland, scsi.ie