Builder insulated our damp wall but it is still wet

Q I live in a 54-year-old detached house. Recently I got a builder to insulate two outside walls in the dining room by putting batons and insulation between them and the plaster. A row of black rings has formed from the ceiling to the floor and on the width of one wall more than the other.

The wall is pebble dashed on the outside. Before we got this done this wall got very damp when it rained. I wonder if there is anything I could paint on the outside of this wall. We are pensioners so money is limited.

A It appears your external walls suffer from damp ingress due to driving rain. The first course of action before doing any internal work would have been to stop this water ingress. This would have been most likely achievable by replacing the pebble dash render. If damp is getting through it is highly unlikely that any paint or coating would prevent this.

The course of action that you and your builder took was to insulate the wall internally but unfortunately it is obvious that the builder left a physical connection between the new and the old internal surfaces providing a conduit for damp to transfer through.

Unfortunately it sounds as if you are now back in the position you were in previously, where you have dampness penetrating through to the internal surface of your property.

I understand that repairing the issue could be cost prohibitive but unfortunately, if damp is getting into your property through the external wall, the best course of action is to stop this problem at the source.

Correct mitigating issues would have been to create a false wall within your property made up of a timber or metal studwork, a gap between the new and old wall and a damp-proof barrier at the back of the new wall. This damp-proof barrier would have prevented the damp and cold from the external wall transferring through to the interior of the property.

A gap, even as little as 10-20mm between the damp external wall and the newly formed internal wall, would have further protected the property against damp transfer.

I would only recommend mitigating issues such as the above when all efforts to resolve the damp ingress have been exhausted or where there is some impediment such as an unfeasibly large cost in comparison to the mitigating issues or restrictive access due to a main road that would require road closure and/or permits from the council.

I recommend you contact a chartered building surveyor for specific advice on whether to attempt to repair the issue or to use mitigating issues.

Kevin Hollingsworth is a chartered building surveyor and member of the SCSI

What is best way to negotiate rent cut?

Q Despite much of the positive news in the media regarding the improving economic climate, my business is still struggling despite my best efforts to reduce costs, including staff redundancies.

One of the biggest costs I am facing at the moment is rent and, despite the fact that business is slow, my rent does not reflect this.

I am considering applying to my landlord for a rent reduction. I have two years left on our 10-year lease and I am wondering what the best strategy for negotiating a rent reduction is?

A Of fundamental importance to the outcome of negotiations is whether your rent exceeds that prevailing in the current market. If you have a legacy lease with an “upwards-only” rent review clause, your rent is likely to be greater than the landlord could hope to secure in a new letting.

Unless you previously waived your tenancy renewal rights, the landlord is likely to be facing the prospect of a court-appointed lease once your existing lease expires and might be better advised entering into negotiations now, with more control over the outcome.

If there is a real prospect of you relocating on lease expiry or putting your business into receivership now, the landlord will have to consider the financial impact of a rental void and the subsequent re-letting costs.

You should begin by researching the current rental market. Look around online and check out the PSRA online Commercial Lease Register.

You should inform the landlord of the difficulties experienced by your business and how a rent reduction will assist your recovery.

I would always advise struggling tenants to show their landlord a set of their most recent audited annual accounts. Such information will help your landlord make an informed decision.

It is important to establish, early on, whether the landlord requires the consent of their lender before a Deed of Lease Variation can be executed, putting the rent reduction on a legal footing.

Finally, a survey, carried out recently by the SCSI, has found that, of the total number of respondents who sought a rent reduction from their landlord, 42 per cent achieved a cut of up to 10 per cent.

Eamonn Maguire is the chair of the SCSI Commercial Agency Professional Group

Our converted attic is very hot at night

Q I recently refurbished my house which included converting the attic into a guest bedroom. Some of our visitors, and indeed members of my family, have complained that the room is too warm.

Are there any measures that can reduce the temperature of this room? Anecdotally, and from some online research, I have heard that insulating the rafters of my roof in the eves could work. Is this true?

A It would be useful to know the type of roof you are referring to in order to ascertain the actual situation. I assume it is a traditional pitched slated or tiled roof with felt underneath.

In any event attic spaces are colder in winter and warmer in summer.

Recent high temperatures resulted in these spaces becoming very hot and uncomfortable.

Placing insulation between the interior and exterior parts of the building serves to retain heat generated internally and conversely acts as a barrier to radiation from the sun rays and so keeping the inside cooler. The addition of insulation should improve your situation.

However careful consideration is necessary when positioning insulation particularly between rafters on sloping roofs. In your situation, the work will be disruptive and you may consider additional insulation on the underside to save removing any plasterboard or lining board you have installed.

You can pump insulation into the void between the rafters, but I would advise against this as it will block air circulation.

Condensation can be generated on the underside of some roofing felts particularly on a cold day when the air inside is warmer.

Air circulation is therefore necessary to dissipate any moisture that is generated. If insulation is fitted between the rafters then a 50mm gap should be formed between the insulation and roofing felt. Air flow through this gap is important. This can be provided by ventilation gaps at eaves and cross circulation to the opposite side or slate vents at a high level.

If you decide to insulate the underside of the existing boarding, then you need to consider the loss of space and additional loading on the rafters.

I would recommend that you seek assistance from a roofing expert or chartered building surveyor on the practical and technical aspects that you should consider.

I would also ask your adviser to check that the attic space used as habitable accommodation is compliant with building regulations especially in regard to fire safety.

If the converted space does not comply with building regulations, then this may have implications for your buildings insurance.

Fergus Merriman is a chartered building surveyor member of the SCSI

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