News

Sep 04

When the owners of a farm house suffering with damp problems needed a damp proofing solution Premier Heritage were on hand to assist with a traditional solution to damp.

This detached, stone built former Devon Farmhouse was refurbished by its previous owners in the 1970’s and unfortunately like many properties of this age was stripped of much of its original fabric, including its lime plasterwork, renders and pointing mortar.

Farmhouse prior to damp proofing taking place

Farmhouse prior to traditional form of damp proofing taking place

In early 2008 Premier Heritage received instructions from its new owners to undertake a full survey of the property for dampness and associated defects and to put forward a specification for remedial works to deal with the dampness present and any associated defects.

Drying out the dampness in the property

Drying out the dampness in the property

The main areas of concern identified by our investigation confirmed the presence of rising and penetrating dampness affecting various walls, although the latter mainly affecting the weather prevailing elevations and most noticeably the front sitting room, rear drawing room and stair area. No structural dampness was identified at first floor level.

As a consequence of the longstanding dampness to the lower sections of the south and western walls, several timber lintels were also showing signs of decay (some having already been replaced) and also death watch beetle activity.

Lintels showing signs of death watch beetle activity and fungal decay

Lintels showing signs of death watch beetle activity and fungal decay

The structural timbers supporting the half landing were also affected by wet rot where bearing into the wall as were numerous skirting and window boards.

To the western wall there was also the added complication of raised external ground levels sloping towards the house and also an obvious, insufficient overhang of the thatched roofing, increasing moisture at ground level and within the walls.

Replaced timbers

Replaced timbers

It was established that the conditions affecting this property had resulted as a consequence of the building’s past refurbishment and the removal of the original permeable mortars and renders used in the buildings original construction (i.e. the lime plaster, bedding and pointing mortar etc). Subsequent replacement with modern cement, being less permeable has resulted in dampness becoming trapped within the fabric of the wall ‘due to its inability to breathe’. This problem has built up over many years being further compounded by the numerous layers of masonry paint applied to the walls over the past 30 years or so!

Premier Heritage’s specification for remedial works concentrated on the removal of the cement materials (both inside and out) to allow the walls to dry down, along with subsequent repairs to structural and joinery timbers. The main contractor was appointed and the works were project managed by Premier Heritage.

The first task was to remove the external paintwork and cement pointing which was impermeable and trapping moisture / dampness within the wall’s, increasing the levels of dampness and internal damage to the building’s fabric. Having removed all external coatings and cement mortar (including that to the interior of the sitting room) the walls started to dry down.

New oak lintels were introduced, where existing were structurally unsound and timber repairs were completed to the interior staircase and landing etc.

Ground levels to the western wall were also reduced, with improved drainage and a vertical slate barrier fitted to the lower sections of the wall to minimise damp penetration.

Following the drying period re-pointing commenced to the exposed stone walls and this was undertaken using a lime based (permeable / breathable) mortar, after which the building was re-thatched and finally redecorated throughout.

The building has now been restored to its former condition and is dry and comfortable as well as looking great!

The finished farmhouse free of damp

The finished farmhouse free of damp

Aug 28

This 1976 brick built Dorset bungalow retained blown fibre insulation introduced in the late 1990’s.

Wall showing rain penetration

Wall showing rain penetration

Rain penetration penetrated the outer masonry and bridged the cavity causing internal decorative spoling and decay to skirting boards. Moisture entrapped within the cavity wall is clearly visible at DPC level externally and is aggravated by very hard impermeable motar.
Saturated perp end joint

Saturated perp end joint

The seriousness of this particular problem became apparent when drilling the perp end joints which were saturated.
Saturated motar between the brick work

Saturated motar between the brick work

Saturated mortar from between the brickwork.
Moisture squeezed from the insulation material

Moisture squeezed from the insulation material

Moisture squeezed from a sample of the insulation material removed.
Remedial costs to remove the insulation and make good, excluding internal repairs and redecoration, was in excess of £2000 plus VAT
Aug 28

Cavity Wall Insulation
(What are the benefits? …..…..DAMP)

From October 2008 all domestic buildings (being built, rented or sold) were required ‘by Law’ to have an Energy Performance Certificate (EPC) to help improve the energy efficiency of the building. The EPC provides an ‘A’ to ‘G’ rating for the building, ‘A’ being the most efficient and ‘G’ the least and to-date a ‘D’ rating is currently being banded as the average.

It is claimed that around a third of heat loss in a house is through its roof and walls and currently there is a government drive (supported by television advertising and the offer of Home Improvement Insulation Grants) to encourage home owners to increase loft insulation and also to fit cavity wall insulation, as it is claimed this can save on average around £180 per annum on heating costs!

However were you aware that by installing cavity wall insulation, whilst you may well be saving some money on fuel costs, you could also be creating a major expense for the future……..damp!

Example of cavity wall insulation

Example of cavity wall insulation

The cavity wall (as we know it) dates back to the early 1900’s and is commonly found in the coastal areas around Britain, used to reduce the risk of rain penetration. In the 1920’s, local building by-laws encouraged the construction of the cavity wall and by the 1940’s it had become the Industry Standard. The familiar cavity wall (as we know it) is two leaves of brickwork, forming a 60mm cavity and tied together with metal wall ties.

Even back in the good old 1970’s concerns were being expressed over Energy Conservation and home owners were then being encouraged to introduce loft insulation and it wasn’t long after that cavity wall insulation was also being recommended.

Fill your cavities with foam, polystyrene, mineral wool or any other material you can introduce through a small hole in the wall and you will save energy and loads of money. Sounds good, but what if by introducing this insulation you increased the risk of damp to your property, which in turn would cause internal decorative spoiling, plaster damage, fungal decay to  structural and joinery timbers and also accelerate the risk of corrosion to the metal wall ties.

Could that really happen? Well the answer is yes and it is.

Paul Carter, the principal of Premier Heritage, has investigated hundreds of buildings over the past 20 years of so, where damp has affected internal decorations etc and found that the damp present was due to bridging of the cavity by the earlier installed insulation materials. Whilst some of these cases were wrongly diagnosed by others as rising damp, most of these buildings (if not all) retained a physical damp proof course, the newest being a 1980’s brick built bungalow in Hampshire.

Ok, lets put this into perspective, there have been thousands of cavity built houses within the UK that have been insulated and a good majority of these don’t currently have nor will ever have a problem with damp. But there are a great number that have and no doubt more will be affected in the years to come! 

Increased rainfall in past years has resulted in a noticeable increase in damp problems affecting conventional cavity-constructed housing, due to moisture penetrating / bridging the cavities and in particular on the weather prevailing elevations and this isn’t a problem relating to current rainfall, but a gradual build of damp over many years.

Rainwater driving into the masonry of a building can penetrate the outer leaf brickwork leading to the wetting of the insulation materials, increased damp penetration and a reduced thermal performance of the material. Poor construction methods, mortar and perp joints, debris within the cavities, dirty wall ties and poor installation procedures by installers all contribute to the overall problem, which generally will result in the need to remove the insulation, which is not only expensive, but will almost certainly cosmetically scar the building when finished. Unfortunately it doesn’t come out through the same hole through which it went in!

So how do you avoid this problem? Well there’s no easy answer to this other than to look carefully at the building’s construction (porosity of building materials) and its exposure to the prevailing weather conditions. If having then decided to proceed, ensure that the chosen contractor / installer, during the survey, checks the cavities  and cavity trays for debris and dirty wall ties, but more importantly offers a system and material that guarantees (preferably insurance backed) that the materials being installed will not transmit / bridge moisture through and into the internal wall!

Alternatively, if you’re still unsure then don’t install.

Examples of Cavity Wall Insulation causing damp:

Cavity Foam Insulation

Cavity Foam Insulation

1970’s block constructed bugalow with poorly installed cavity foam insulation and debris bridging moisture via wall ties, cost around £800 to remove and rectify internal damage caused.

Polystyrene bead cavity insulation

Polystyrene bead cavity insulation

1930’s brick constructed house with polystyrene bead cavity wall insulation. Caused extensive damp to rear elevation walls, cost in excess of £3,000 to remove insulation and rectify internal damage.Polystyrene bead cavity insulation
Polystyrene bead cavity insulation

Polystyrene bead cavity insulation 2

1920’s brick constructed house, south facing elevation with polystyrene bead insulation and poor quality mortar. Caused extensive damp to internal decorations and accelerated corrosion of wall ties (rusting ends just visable), cost in excess of £3,500 to remove insulation and install new wall ties.
Aug 24

Damp and fungal decay survey at historic mill 

Premier Heritage are pleased to have been appointed to undertake Timber and Damp surveys of the former Tonedale Textiles Mill in Wellington, Somerset.

Tonedale Mill was established in 1790 by the Fox family and was, for many years, the largest integrated woollen mill in the South West employing around 2000 local residents. The original site extended to approximately 12.6 acres and provided a range of stone and brick built Grade II and Grade II* Listed buildings.

Tonedale Mill

Tonedale Mill

The Mill is of particular historic significance as it retains a full complement of buildings representing the complete manufacturing process, from processing the raw wool through to yarn spinning and the preparation of woollen and worsted cloths. During the Boer War the Tonedale dyers also developed the dye ‘khaki’ leading to the end of British soldiers’ “redcoats”.

Evidence also remains of the development of different forms of power generation: from the early water powered mill, to the steam powered mills and finally to the electrical generating complex in the centre of the site. The mills also had specialist buildings for the manufacture of metal and timber components for both buildings and machinery maintenance.

The property now benefits from detailed planning permission and listed building consent and Hydon ( www.hydon.co.uk )and their joint venture partner, Kenmore Homes, are developing in excess of 150 residential units and also commercial space, combining some minor new build with a sensitive conversion of the existing buildings, maintaining much of the original internal fabric.

As with many sites of this type, it has fallen into a state of disrepair and various buildings are now affected by significant damp ingress and varying forms of fungal decay, including dry rot.

Premier Heritage have been employed to initially undertake the timber and damp condition reports on the various stone and brick built buildings, which will include the inspection of over 800 original windows, all of which are to be completely renovated.

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