Your queries answered

Q We are renovating a 1970s bungalow and are busy getting quotes for replacing single-glaze windows with PVC. Each company is, understandably, pushing their own specifications, some stating A-rated are essential, others saying foam-filled frames are the new best thing in windows. Is it better to pay the extra for triple glazing for the north-facing rooms? Are foam-filled frames worth it? Are there common specifications I should be looking for in windows when shopping around?

AThe main reason people upgrade or renovate their home is to improve living standards and create a more comfortable building to live in. Improving the energy efficiency of our existing housing stock is important, both for the environment and for the occupants. The key in relation to any thermal upgrading is to consider it in the context of the building as a whole, rather than as deficiencies in isolation. As part of your renovation you should also consider the thermal efficiency of the attic, walls and floors as well as preventing or reducing draughts. Typical heat loss is 35 per cent from walls, 25 per cent from the roof, 15 per cent from floors , 15 per cent through draughts and 10 per cent from windows.

All windows should come with a window energy rating and label. The ratings, ranging from A-G (A being the most efficient), were introduced to facilitate a clearer understanding of the energy performance of your window. The label gives the breakdown of the specification components relating to the rating and, more importantly, the U-value (or heat retention) of the window. Current Building Regulations require that the U-value should be a maximum of 1.6 W/m2K. The window energy rating applies to frame and glass.

Foam-filled frames are shown to improve overall energy efficiency, but given the surface area (of the frame), the return on your investment is marginal. Triple glazing will also improve energy efficiency, but its effects will be maximised only when used in conjunction with a high level of thermal upgrading throughout the building, irrespective of orientation. Triple glazing also inproves sound insulation.

Andrew Ramsey is a chartered building surveyor and member of the building surveying professional group of the Society of Chartered Surveyors Ireland. SCSI.ie

Q In late 2010, I moved from my house in Dublin (which I own) to a cottage in the country, purchased in 2006. I had registered the cottage with the county council for payment of the second-home tax since it was introduced. I haven’t changed this. My house in Dublin is rented. Do I need to change second-home registration to my house in Dublin and pay property tax on my cottage as this is now my primary residence? How do I go about doing this? (All my Revenue-related correspondence now comes to my cottage in the country – I am self-employed).

ATo summarise briefly: you are the owner of a house in Dublin. In 2006, you purchased a cottage in the country. In late 2010, you moved from Dublin to the cottage and rented the house in Dublin. By way of background, the Non-Principal Private Residence (NPPR, nppr.ie) charge was introduced in 2009, so the sequence of payments should have been as follows: in 2009 and 2010 you had a NPPR liability on the cottage while you lived in Dublin, and in 2011 and 2012 you had a NPPR liability charge on the property in Dublin, as you had moved to the cottage. Even though you may have recently rented the house in Dublin, you can have only one principal private residence, and all other residences rented or not) are generally liable for the NPPR charge.

As I understand the case, you are liable for significant arrears on the Dublin property, possibly up to €960 to cover 2011 and 2012, and you should seek to have this regularised as soon as possible as the arrears continue to accrue. As you present the facts, it looks like genuine error – you made NPPR payments, just on the wrong property, but to my knowledge there is no mechanism for switching payments already made. You can apply for a refund on the cottage, but you get back only what you paid, which will not cover the arrears.

I presume you also paid the household charge ( householdcharge.ie) last year for both properties. The new property tax, which replaces the household charge for this year, is payable on both properties and in addition to the NPPR, which needs to be paid on the Dublin property. Revenue are writing to all homeowners in March to advise in relation to the procedures for payment of the new tax.

I would advise you to contact the relevant local authority of the Dublin property, explain the situation to them and seek to remedy it as soon as possible.

Ed Carey is a chartered surveyor and estate agent and is chairman of the residential agency professional group of the Society of Chartered Surveyors Ireland. SCSI.ie

Q Last year we added additional insulation to our attic. The benefits of this were seen immediately. This winter, especially with low temperatures, we have noticed build-up of water on the underside of the roofing felt. We have ensured the insulation is not right up against the eves. My concern is that the roofing felt may not be breathable and may need to be replaced.

AIncreasing the amount of insulation has led to colder roof voids. If, on a cold day, there is condensation on the underside of the felt, then there is a need to improve the level of ventilation.

I have seen such condensation in homes where I have recorded ineffective cross ventilation. Most modern homes have projecting eaves with horizontal pre-formed soffits and perforated holes. The perforations are sometimes installed at irregular spacing and do not always correspond to the opposite side. Older homes may have flush fascias and no venting.

For a typical pitched roof, the minimum standards recommend an area that is at least equal to a continuous 10mm air gap at eaves. For a “lean-to” roof, the same rule applies but with the addition of ventilation at high level at least equal to a continuous 5mm air gap. For roof pitches below 15 degrees, the eaves ventilation should be 25mm wide. The minimum standards are not always achieved.

Ensure insulation is free from the eaves. Check the amount and spacing of the soffit vents. Compare these to a continuous 10mm air gap around the building. If it’s a “lean-to” roof, make the same observations but note high-level venting is necessary. Gables allow the addition of vents and closely spaced slate vents can help. There are proprietary continuous ventilators that are placed under the front row of slates. A roofer will need to remove and refit the lower four courses. Preformed vent slots can also be placed between the insulation and felt in the attic. Also check insulation is evenly distributed and placed over and not below the water tanks.

Replacing the felt with a breathable membrane is a costly solution. It will mean removing and reinstating roof tiles and battens with wastage and/or breakage requiring new materials. The membrane allows movement of water vapour through it, which is an improvement on the impervious felts previously used. Some manufacturers claim these do not need ventilation, but they have not been tried and tested over a significant period, so for a healthy roof void you need a draughty void.

Improving the ventilation and evenly distributing the insulation should deal with your problem. The type and construction may even have a bearing on the problem. If in doubt, I advise an inspection by a registered building surveyor or registered architect.

Jim Drew is a chartered building surveyor and member of the Society of Chartered Surveyors Ireland. scsi.ie

Got a query?

Send your queries to propertyquestions@irishtimes.com or to Property Clinic, The Irish Times, 24-28 Tara Street, Dublin 2. This column is a readers' service. Advice given is general and individual advice should always be sought