There is water under my house what should I do?

Q My husband and I recently purchased a house. In the process of getting to know our neighbours, one of them informed us that there may be water under the house. This neighbour had recently discovered water under his property and had informed the previous owners of our property. However, nothing was done. Recently I took the carpet out from one of the rooms on the ground floor, followed by a section of the floorboard and indeed it does seem that there is water under the house. From what I can see, the water was quite low down but there was a lot of it. What impact will this water have on my property and what do I need to do to minimise its impact on my property.

The level of water in the ground will vary and is generally known as the “water table level”. The water table level tends to be fairly static but can vary between summer and winter conditions and clearly can rise following heavy or prolonged rainfall. In low-lying ground or in areas along the coast, where the water table level would not be that much lower than the finished ground level, the possibility of water underneath the suspended timber floor is in fact quite possible and is something that we have come across on numerous occasions.

When one is building or designing a house it needs to be considered a bit like a boat in that part of the house, ie the foundation/base is below the ground, and this could be below the water table level. In other words this is in a permanently damp location. For this reason, damp proof courses are incorporated in the walls, and damp proof membranes in the floor, in order to prevent water rising up through the house. This phenomenon has been known and recognised for years. It is most likely this issue has been going on for a very long time and no doubt most of your neighbours will be experiencing the same issue.

The good news is that more often than not, this is not a major problem and you could possibly just ignore it.

The potential issues for concern are foul damp odours and/or a risk of decay to the floor timbers due to excessive dampness. However, provided that there are good strong levels of ventilation into the sub floor void (the space between the floor and the ground), which can be provided through air vents at a low level in the walls, these issues are unlikely to materialise.

If the water level is very high, there may be some merit in attempting to reduce this by forming a suitable French drain at a lower level around the perimeter of the house to alleviate the issue somewhat. The other potential issue for concern is that it does indicate that the ground water table is relatively high when compared with your actual ground/floor level and this may be an indication that you will be more susceptible to a risk of flooding, and as we know of late, unfortunately there are many properties which have been built in known and potential flood plains. It might be prudent to seek further information as to the risk of flooding in your area.

Val O’Brien is a chartered building surveyor and a member of the Society of Chartered Surveyors Ireland; scsi.ie

Sub-let deposit

Q I have been renting a house now for some time. I have a lease and about eight months ago I started sub-letting one of the rooms in the house with the landlord's permission. Last week one of my licensees moved out without providing me with any notice and is now requesting the return of her deposit. Given that she didn't provide me with any notice, and given the fact we had a verbal agreement prior to her moving into the house that she would give me a month's notice, am I within my rights to keep this deposit? It should also be mentioned that she has not paid a number of utility bills. She is now threatening to go down the legal route to get her deposit back. Any advice would be greatly appreciated. Is the law on my side?

Sub-leasing occurs when a tenant permits another party to lease the rental property that the tenant has leased from the landlord. The tenant then assumes the position of landlord (known as the head tenant) in relation to his or her subtenant. Under the current legislation, Residential Tenancies Act 2004, a landlord is entitled to 28 days’ notice that a tenant is intending to vacate a property even if a fixed-term lease is not in place, once the term of the tenancy has been less than six months. In this case the term was eight months albeit a verbal agreement and consequently a notice of 35 days ought to have been given to the head tenant. The fact that a number of utility bills are also outstanding and not paid by the subtenant would also validate a reason to retain the deposit. You do not mention if any rent is outstanding at the time the subtenant vacated and this of course would also validate a reason to retain the deposit. Karol Jackson O’Shea is a chartered residential agency surveyor and a member of the Society of Chartered Surveyors Ireland; scsi.ie

Loft insulation

Q I have no access to my loft void. However, I need to insulate this space as I have noticed, as we enter into the winter, that it is becoming quite cold. In terms of undertaking the work by myself, I am a bit concerned for my safety. The house was built during the 1920s and I was wondering that if I knock through this space could I expect to find the joist type loft that you would find in modern buildings in order to support my weight and for the house insulation? I am also concerned that I might encounter asbestos. Is this a possibility?

Insulating an attic is the first and best way to preserve heat in a home but unless you are experienced at building work or at least DIY then you should not undertake insulation in an attic or loft space. Besides the dangers of falling there are several other issues which need to be considered.

The first thing is to gain access to the loft itself. There probably was an access hatch at some point that may have been sealed up by previous owners. You should get a competent joiner to create a loft hatch and have a sealed and insulated item fitted. There are a number of inexpensive units available from good builder’s providers for this. Choose the best and also consider a composite unit with a ladder inbuilt.

The next process would be to survey the attic to ensure there are no infestations such as rot, insects, rodents or indeed asbestos as you note. Contact a local building surveyor who will inspect and identify whatever is in the attic and will provide advice on how best to proceed. It is very unlikely but not inconceivable that asbestos might be in the roof of a 1920s house. If any fibrous material is noticed, do not tamper with it and get expert advice – see hsa.ie/eng/your_industry/chemicals/asbestos/ for information.

If there are bats roosting they are a protected species under the Wildlife Act 1976 and any work in the loft must be undertaken under the direction of the National Parks and Wildlife service, see npws.ie. It is also possible that a 1920s roof might be slated with man-made asbestos slates and laid without an inner lining or ‘sarking’ felt, so dangerous fibres may have fallen from the underside of these slates and should be watched out for.

Make sure the ventilation at the eaves is preserved. Another thing well worth considering is fitting a “vapour barrier” under the insulation. It consists of a flexible plastic sheet at least 300microns thick laid over the ceiling members and sealed at all junctions. It stops condensation forming in the insulation and helps roof timbers that otherwise might get damp under certain conditions.

You might also consider future access for maintenance of tanks etc because supports for walking will be hidden under the insulation. A very important consideration is electrical wiring. If it is old, get a registered electrician to test it.

Apart from all that, there is no reason why a fit or able person cannot install insulation with due care taken. Most manufacturers provide DIY advice about installing insulation and you should consider the thickest you can afford but at least 300mm thickness of quilt.

Grants are available through seai.ie under the Better Homes scheme and SEAI have a list of approved insulation installers so this might be your best way to proceed.

Fergus Merriman is a chartered building surveyor and a member of the Society of Chartered Surveyors Ireland; scsi.ie