Property : Cheshire

Instructions To inspect the property and report on any issues relating to timber or dampness.

Background The clients are in the process of purchasing the property and a chartered surveyor has asked them to seek further guidance on the above issues. In particular, Miss BD has asked me to pay particular attention to the following:

Floorboards in the front room beneath the bay window
Concrete flooring in the kitchen
Bulge in the ceiling of the middle bedroom
Floorboards sloping in the dining room and crowning.
Damp walls generally
Air vents in the property
Bressummer (lintel) over the dining room window
All timbers generally.

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

Limitations Nil

Restrictions Nil

Date of Survey April 2005

Weather Fine and clear

Type of Property A brick built mid terrace under a blue slate roof. The property faces in a North of East direction and was probably built in the early part of the 20 th century.

External Observations The property consists of an original terraced section with an addition (referred to as an ‘outrigger’ by the chartered surveyor) abutting it to the rear at ninety degrees.

The external walls of the outrigger are 9" solid brickwork and these differ from the main part of the house, which is built with 10" cavity walls. In the front external wall of the main part of the house it is difficult to see a damp proof course (dpc) although most properties built after 1900 had them included. It is probably that the one in this property is slate or bituminous roll, set back from the front of the brickwork and pointed in.

The extension does have a dpc and this appears to be of a plasticised material resembling PVC. Furthermore, there are signs that an injection dpc has also been installed at a later date.

The roof is the original blue slate roof but next door (to the right hand side when viewed from outside) the roof has been renewed and flat concrete tiles have been used. Because of the difference in thickness between these tiles and blue slates there is a step between the two roofs. This has created a gap that has been closed by the use of ‘Flashband,’ which is a proprietary type of flashing.

To the front of the property the brickwork has been painted (several times) with a decorative finish. This paint extends from ground level to a height of approximately one meter and is peeling off in several places. When a section was removed, severe efflorescence could be seen on the brickwork beneath (Efflorescence is salt that is deposited when masonry is drying out).

There were two airbricks beneath the bay window and two smaller vents beneath the front door threshold. Upon inspection the two beneath the window were unobstructed but it was difficult to see if the ones beneath the step were also free. In any case the mesh protecting them is too small to allow an adequate airflow through.
There were no high ground levels to the front and drainage and rainwater goods appeared satisfactory.

On the outrigger roof is a shared chimney. The flashing on this chimney is defective and requires attention.

At the rear of the building, the lower reaches of the brickwork to both the original part of the house and also to the extension have been painted in a similar manner to that at the front.

There is a flagged pathway beneath the rear kitchen window. At the left hand side of this path (when viewed from the outside) these flags are too high and they are bridging the damp proof course.

Internal Observations Loft

There were no signs of any insect infestation or fungal attack (wood rot) in the loft and all timbers are in good condition. I could not find any reason pertinent to my inspection why there should be a dip in the bedroom ceiling but I expect it’s due to the weight of the lath and plaster which is bowing the ceiling members. These are only 3" x 1-1/4" in section and, for your future reference, care needs to be taken when walking on them.

The granular loft insulation requires upgrading to modern standards, which call for 250mm depth of insulation. When this is being done great care must be taken to preserve the eaves ventilation, which presently is good.

In the outrigger’s loft, at the rear, there is clear daylight to the side of the shared chimney. This is the result of the defective flashing referred to earlier. Water is entering at this point but has not, as yet, caused any problems.

The dividing wall between this house and the one to the left (when viewed from the front) does not reach full height at its rear section and there is a distinct connection between the two houses.

First floor

There were no issues on this floor that require attention. Carpets were lifted where possible and neither insect infestation nor fungal attacks were noted.

Ground floor

I will deal with timber issues first:

Carpets were well fitted throughout the living room and dining room and there was no access to the sub floor areas. Accordingly I lifted the carpet in the front room and created two access traps, one in the bay and another to the other side of the room. Using these traps I was able to crawl beneath the whole of the property.

All sub floor timbers are in good condition and free of rot or insect infestation. The timber beneath the hall (joists and floorboarding) has been replaced within the recent past and has been laid on damp proof membranes. However, I could not ascertain whether pre-treated timber has been used.

Moisture meter readings were taken of a representative sample of timbers and these indicated that moisture content was acceptable (less than 20%), except for those sections of timber that entered and rested upon the front wall of the property, especially in the bay section.

I could see no reason, pertinent to my survey, for any crowning or other distortion of the floor.

There was adequate inter-ventilation of the sub floor, i.e. the sleeper walls allowed air circulation, but this itself is limited by the amount of air bricks included in the outside walls, of which there are two main ones to the front plus vents beneath the threshold and one full sized air brick at the rear. The slab upon which the kitchen extension sits will also restrict air flow from front to back.

The joist ends where they rest in the footings at the front of the property had moisture contents in excess of 25% and as such are at risk of fungal attack. This is not yet occurring but even though they have been in situ for eighty years or so, it may still happen. I could not see a dpc on the inside wall either.

Dining Room lintel

To examine this lintel without destroying the surrounding plaster work is not possible and, without the written consent of the vendor, I could not attempt this. The lintel over the window was examined and tested for moisture content. It proved to be satisfactory.

Damp

Moisture meter profiling was carried out throughout the ground floor of the property. All internal walls, i.e. party walls and load bearing internal walls provided satisfactory profiles. Others, including the front wall, the kitchen walls and the angled wall between the kitchen and the dining room gave high moisture meter readings that need further consideration.

Discussion The main issues that require further attention revolve around the timbers which rest in the front wall of the property and the high moisture meter readings obtained in those walls previously mentioned.

Dampness in timber can have two causes. It could be the result of the timber coming into contact with a wet material, such as masonry, or it could be the result of moisture it has absorbed from the atmosphere. Timber, being hygroscopic absorbs water quite easily and there will always be moisture contained within it. Below 20% moisture content (m.c.) this will not cause a problem. Above 20% m.c., fungal attack can initiate although in practice a m.c. of 25% plus is required before a fungal outbreak will occur.

The joists in the living room, where they rest upon the front walls, have a m.c. of 25-27% and thus they are in danger. The constituent parts of this m.c. are undoubtedly moisture absorbed from the brickwork as well as hygroscopic moisture. Other parts of the same joists and other joists that are not in contact with the front wall have a m.c. of between 16 and 18%. The excess content in the end portions of these joists must be the result of absorption from the brickwork. This degree of excess is not severe and indicates that the brickwork, although not dry, is not suffering from rising damp to any notable degree. Nevertheless, an attempt to alleviate this problem (joist ends) must be attempted. (see conclusions).

With regard to the moisture profiling in the living room, dining room and kitchen:

All the walls are built off the same ground and, as only the external walls of the house and the solid kitchen walls in the outrigger are exhibiting signs of dampness or providing high moisture meter readings, there must be factors affecting these walls which the other, dryer walls, do not have.

Also, because a wall displays high moisture meter readings it does not necessarily mean that it is either excessively damp or presents a serious problem. It is the effect of any dampness, on other materials that are in contact with that wall which must be considered. These include such things as flooring timbers, skirting boards and decorations.

In my opinion, the front living room wall has a higher moisture content than the other walls in this room because it is suffering from condensation.

There may also be a degree of damp rising from the ground and crossing the slate/bituminous dpc but this is secondary to the main problem which, when solved, will lower the moisture content to a satisfactory level. Factors that are allowing condensation to take place are:

1. It is an outside wall
2. It faces in a Northerly by Easterly direction
3. It has a non-permeable coating on the outside.

The first two items will ensure this wall always has a lower temperature than the other (internal) walls and the third item is seriously hampering the evaporation of moisture caused by the condensation.

As far as the moisture in the kitchen walls is concerned:

The construction of the kitchen walls differs from those in the main house by virtue of the fact it is a solid 9" wall whereas the external walls of the main part are 10" cavity walls. Also, as previously mentioned, it has a dpc already installed and at some stage a further injection dpc has also been added.

Despite the two dpc’s, all of the walls in this area still give high moisture meter readings and there is visible damage to the decorations on the lower rear right hand corner of the room beneath the window

It is highly unlikely that the original dpc has failed along its entire length and in fact it probably hasn’t failed at all. The introduction of a chemical injection dpc at a later date will  have been unnecessary because the cause of the dampness has been misunderstood. Rising damp has been diagnosed when in fact condensation was, and still is, the cause.

I do not intend to go into great detail in this report about the causes and effects of condensation. Instead I have included a booklet that you may wish to read.

Because of its solid wall construction this section of the building is extremely prone to condensation, even at first floor level, and you will need to adopt the measures described in the booklet to combat it. Also, this room has been decorated in a material which, along with the paintwork on the outside, effectively forms a ‘sandwich’ that does not allow the moisture within the wall to evaporate.

Finally, the high ground to the rear (which was mentioned in an earlier paragraph) is bridging the original dpc and as this is a solid wall, dampness is progressing through the brickwork.

This is showing on the inside and may have caused superficial damage to the plasterwork..

As for the floor; it is not possible to tell whether it has been laid on a damp proof membrane, but it probably was. Again, condensation will have occurred on this floor since it was first laid and it would always have been damp. In an effort to cure this, a bitumen coating has been applied to it. This will have negated any issues of penetrating damp but it will not have affected the condensation problem. On top of the bitumen, a coat of levelling compound has been employed and then a decorative vinyl coating of some sort.

This arrangement can lead to standing water on the floor during times of high moisture content, such as when cooking or the washing and drying of clothes is taking place. Again, the solution is the control of condensation.

The areas where the bitumen layer has been missed will probably have been where old kitchen units stood. You can fill/level these with a sand and cement screeding laid on top of a suitable damp proofing substance such as Visqueen, which is available from builder’s merchants or B&Q. A levelling compound can then be used to finish off the surface to your requirements.

Conclusions

This property, in common with most houses of its era, has poor insulation levels, especially in the roof and outside walls. Over the years the ventilation has been reduced by the inclusion of storm proof sash windows and the restrictions on air flow occasioned by the use of gas fires. Also, there is no mechanical extraction in the kitchen. With the intermittent use of heat and lack of ventilation, condensation will have been occurring on outside walls and other cold surfaces for many years. The decorative paintwork that has been applied to the external walls will have impeded evaporation from them and this has allowed the moisture content of these walls to build to current levels.

Adopting measures to combat condensation are essential but you must be aware they will not dry out the property overnight. It will take many months for this to happen and the time taken will depend on your ability to control ongoing condensation. As you will be entering the property during the summer months, this may be an opportunity to increase the ventilation on a regular basis. I would also advise you to remove the surface decoration in the kitchen and allow the walls to ‘breathe’ more easily.

Having examined the sub floor areas of the property I conclude that there is no justification for major chemical treatments under COSHH (Control of substances hazardous to health) regulations. Localised treatment of joist ends will be sufficient.

Other recommendations are as follows:

1. The flashing to the rear chimney stack should be repaired

2. The thermal insulation in the loft should be upgraded in line with current requirements (at least 200mm on top of what is already there.

3. Consider isolating your property from that next door by building up the dividing wall.

4. Increase the size, and tidy up, the edges of the loft access area.

5. The ends of the joists which rest in the front wall should be treated with a Borax based preservative paste such as Boron Ultra Gel. Access to these joist ends is now easy because of the newly installed trap and could be carried out by yourselves. If you intend to do this, please contact me and I will give you purchase details. Alternatively I could carry out the treatment for you if you so require.

6. The flags to the rear kitchen, which are adjacent to the wall itself, should be lowered by at least 4".

7. The paint that has been applied to the front and rear external elevations must be removed in order to allow excess moisture in the property to evaporate.

8. All measures to reduce condensation should be employed, particularly those which deal with the concept of moisture production. Further action on damp walls may be necessary in the future but an effort to control the problem by paying attention to the condensation issues must be attempted first. These further actions may include a recommendation on cavity wall insulation and dry-lining in the kitchen.

9. The sub floor ventilation, whilst not quite in keeping with current Building Regulations, has nevertheless worked satisfactorily beneath the main section of the house for some considerable time. However, the refurbishment of the joists and floorboards in the entrance hall would suggest that the small vents beneath the threshold are inadequate and may have caused problems in the past. You should therefore consult with a local builder to see if it is possible to increase the size of these vents, perhaps by the simple expedient of core drilling larger holes along the front of the step and covering them with a suitable grille. If you venture further along the street you will see that other people have altered the original arrangement and made their vents larger. You should adjust the ventilation in the threshold such that an area of 100cm2 is achieved.

10. The ‘Flashband’ used on the roof has a limited life span and a more permanent arrangement should be adopted. This could consist of flat coping stones bedded onto the roof over the joint and pointed to prevent water ingress. A competent roofing contractor should be consulted regarding this matter.

I trust the above is satisfactory for your purposes but should you require further clarification, please do not hesitate to contact me. I assure you I am interested in your problems and will be happy to assist you in the future in any way I can. 

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

Qualifications BWPDA Certificated Surveyor in Remedial Treatments

Date of Report April 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.