A cautionary tale: Don't just brick up fireplaces and then expect them to sit quietly and behave themselves. Lack of maintenance will cost this lady thousands!

This horror story was brought about by the closing (and forgetting) of a fireplace in the basement chimneybreast. No further thought was given to it and, as the soot fell down and the moisture rose up, the plasterwork and associated skirting boards began to suffer.  Adding to the problem was the general condensation occurring in the room.  I see dozens of bricked up fireplaces that people consider to be 'just another part of the wall'.  They have no idea what could be happening in there. The photo speaks for itself!

Instructions To inspect the chimney breast in the basement and advise on problems of dampness in it and the adjacent alcoves.

Background The client has owned the property for some considerable time and problems with the chimneybreast have gradually worsened over the years.

Disclosures I have no affiliation, financial or otherwise, with the client or the property.

Limitations Limited to the above.

Restrictions Nil.

Date of Survey June 2005

Weather Fine

Viewing Orientation All observations are made as if looking towards the house from the front.

Type of Property A late Victorian or early Edwardian terraced property built of brick under a slate roof. There is PVCu double-glazing and gas fired central heating.

External Observations The pots on the chimneystack serving the basement have square open tops. It was difficult to see any other details because of height and other buildings, which obscure the view.

Internal Observations Rear Basement:

This area has been divided into two rooms, the main one, presently used as an office, is ‘L’ shaped and the smaller room, which is to the rear, serves as a laundry room.

There is a PVCu door to the rear from the main room and a PVCu window. In the laundry room is a PVCu window, a lavatory, a central heating radiator and a washing machine, which is plumbed in.

Also in the laundry room were clothes drying facilities (creel) and this was currently in use.

Both windows have a trickle vent facility but, at the time of my visit, only the one in the laundry room was in use.

The floors in both rooms are solid and have a sand and cement screed.

Dividing the two rooms is a stoothing partition wall that is plaster boarded but not skimmed. The plasterboards were in contact with the screeding on the floor.

This partition wall intersects with the chimneybreast at right angles and divides it in the approximate ratio of two thirds to one third with the smaller room being to the rear.

The opening in the chimneybreast itself has been sealed with concrete blocks and a small hole has been left at low level. Slightly above and to the left of this hole is another one, which has been completely blocked.

It was noticed that there are substantial deposits of soot on the floor of the (now enclosed) hearth and these are beginning to accumulate and rise up the walls of the chimneybreast.

The rendering/plasterwork to the chimneybreast and also to the alcove to its left hand side has disintegrated and is falling away. This is probably due to a sulphate action with a contaminant such as gypsum plaster.

The timber skirting boards to the left hand side of the chimneybreast and alcove have been attacked by the fungus Coniophoria Puteana (wet rot) and have been virtually destroyed. This is a direct result of dampness.

The timbers in the partition wall, where they are in contact with the chimneybreast, have high moisture contents and are also in imminent danger. (They may already be suffering from rot but it was not possible to verify this).

In the office, the small timbers that are attached to the right hand side of the chimneybreast and which carry the micro-bore central heating pipes also have high moisture content and are in danger of rot.

It was noticed that there are a series of injection holes in the lower reaches of the alcove adjacent to the chimneybreast in the larger room. These are probably mirrored in the other room but I cannot be sure.

Moisture meter readings taken throughout the entire area of the chimneybreast and alcove walls indicated an excess of moisture. Its source will be discussed below.

Discussion It is probable that an attempt to control dampness in this area has been made in the past. This is evident by the injection holes and the re-plastering of the affected areas. Unfortunately other factors have conspired to negate these efforts and these are now beginning to have a marked effect.

Sealing the chimneybreast in the manner employed not only allows condensation to occur within it, it also hinders maintenance, particularly sweeping. Thus, as rain enters the open pot at the top and falls into the stack, it carries soot deposits with it and these accumulate on the hearth beneath. Ammonia salts contained within soot are hygroscopic (they absorb moisture) and, as they leech into the surrounding brickwork and stone, they will absorb moisture from the atmosphere and thus contribute to the moisture content of the walls. Naturally the soot will also be damp.

The basement itself is very prone to condensation. The windows that are installed have little in the way of ventilation facilities and these relate only to the ability to either open or close the top light. Although there is a trickle vent setting on these lights, it is difficult to operate and, over the years, will have been ignored on many occasions.

The fact that washing and drying of clothes takes place in this poorly ventilated room will mean that moisture production can, from time to time, be very high. Consequently condensation will frequently occur on any cold surface. (I have enclosed a booklet on condensation that you may wish to read).

I also suspect that during renovation work the sand and cement rendering that was applied to the affected parts was ‘hurried’ along by the addition of gypsum plaster to the mix. It is also possible that the angle beads on the arrises of the chimneybreast were set in place using gypsum.

This mix of gypsum and cement has led to a sulphate attack that has destroyed the render coat. This also leaves it prone to moisture absorption.

Conclusions The work required to repair the damaged walls is in addition to an ongoing effort to combat condensation. If this is not done, the surface of the walls will always be affected by dampness and the benefits to you will be limited.

The following work will be required:

Instruct a competent roofer to install a cowl on the chimneystack that serves this flue. You may also wish to consider similar cowls on any other open pots and a general check of the flaunching and pointing should also be carried out at the same time.

Remove the timber and plaster board partition wall. If this is not in line with your requirements, then remove the first 600mm of it where it abuts the chimneybreast whilst repairs are being carried out. When you re-install it, isolate the partition wall from the chimneybreast by means of a plasticised damp proofing membrane.

Also, ensure the plasterboards do not touch the concrete floor by leaving a gap of at least 25mm and ensure any plaster skim does not go beyond this level. This applies to the whole wall, not just the repaired section. When fixing skirting boards, use pre-treated timber to guard against rot and insect attack.

Sweep the chimney

If you intend to replace the blocks after the chimney has been swept, ensure a ventilation area of 250mm x 250mm is included. Use of proprietary airbricks will suffice for this purpose, but two will be necessary. These should be at low level in the first course of block work, which should be laid on a damp proofing membrane. You should also leave an aperture, which is capable of being closed, through which to sweep the flue.

Remove rotten skirting boards and discard.

Hack of the defective wall plastering to a height of 1800mm. Re-plaster using a sand and cement base coat in the ratio of 4:1 sharp sand to cement. A waterproofing agent, such as FebProof or similar, should also be added to the mix

If using angle beads on the arrises, do not use a gypsum-based fixative.

Skim with Carlite finish or a proprietary renovating plaster finish.

Read and employ the methods to control condensation, which are contained in the attached booklet.

I trust the above is satisfactory for your purposes but if you require further clarification please do not hesitate to contact me.

Surveyor Patrick F Doyle CSRT M. Inst. R.T.S.

Qualifications Certificated Surveyor in Remedial Treatments issued by the BWPDA.

Date of Report June 2005

Signed Surveyor

The above findings are based partly on the interpretation of results from a standard non-destructive inspection; this, by necessity, has limitations. If you require confirmatory/definitive diagnosis of my findings then this can be undertaken by the use of destructive methods of investigation: these will involve some damage and costs.