BUILDING SERVICES & SURVEYS
RELATIVE HUMIDITY – MOISTURE – DAMP - AIR QUALITY
CONDENSATION - WATER LEAKS
Horton Levi damp detection surveys include in-depth physical
inspections, endoscope intrusive investigations, where required, and 8-14
micron infra-red scanning of walls and roofs as appropriate. Comprehensive
investigations are also available and can include some or all of the
• CCTV Roof Drain Inspections
• Carbon Monoxide Concentrations
• Temperature / movement
• Relative Humidity
• Dust Concentrations
• EMF. Electromagnetic Fields – Leakage and Emissions
• Infrared Thermography to identify areas of high moisture /
• Radio Frequency metering for sub-surface moisture inspection
• Electromagnetic wave inspection to ‘map’ and trace damp.
• Endoscopic Video inspections
Hard copy reports and all survey
data on CD for client viewing/archiving on a PC is standard as a part of our
Horton Levi specialises in flat roof surveys and inspections.
We have developed
techniques to 'Map' the extent of moisture or water ingress beneath the
roof felting or covering. In most cases, the source of the ingress
is apparent from the infra-red data.
Because we can usually
pinpoint the areas where there is moisture beneath the felting and trace
the path of entry, these specific areas can be repaired. Most
roofing companies will repair large sections to ensure the problem is
contained however this can be very costly compared with our survey.
Our surveys are totally
impartial and we are not connected or associated in any way with roofing
Damp or moisture is a
very efficient conductor of heat energy, and under the right
conditions, rising and/or penetrating dampness can be visualised
through a thermal imager giving the precise boundaries of the
problem saving a vast amount of time using conventional damp meters.
Please contact us for our brochure.
below are a photograph and a typical thermal
image showing moisture beneath the roofing felt.
Yellow areas show moisture beneath
Horton Levi specialises in locating water
leak entry points in buildings. Much of our work is with commercial
buildings and flat roofs. Our company has provided this service since
1992 and has constantly invested in the latest equipment as well as
developing our own.
services can employ some or all of the following techniques:
Red in this thermal image is
underlying moisture. Moisture trails show that water is
entering from the parapet.
Using advanced rectification
techniques, we can overlay a thermal image with a
This enables easy
identification of problem areas as shown in the example on
The image to the right is a
blend of the thermal and photographic images above.
Red shows the underlying moisture.
DAMP – RELATIVE HUMIDITY – MOULD
Relative Humidity is usually measured as a
percentage of water vapour in the air. The amount of vapour contained in the
air can vary with air temperature and pressure.
‘Comfort Level’ - Effect of Humidity / Temperature Variations.
The effective ‘comfort level’ in a home or office can vary with temperature
and humidity. Below about 14° C, humidity has little effect on temperature
feel but at normal house / office heated temperatures of about 22°C, there
can be a significant difference in ‘comfort level’. When humidity is low, a
normally warm temperature can feel cool owing to faster evaporation of body
perspiration. Conversely, in higher humidity situations, perspiration is
slowed providing a warmer feel at the same temperature.
Heating, Ventilation, and Air-Conditioning (HVAC) systems
HVAC systems should provide air at comfortable temperature and humidity
levels and filter indoor air contaminants. HVAC systems that are poorly
operated or maintained can contribute to poor indoor air quality.
Effect on Buildings and
materials (wood, plaster, decorative / paintings etc) absorb water
vapour from the air. Materials will therefore absorb more moisture in
high humidity situations and release moisture as the humidity lowers.
Moisture soaked plaster or plasterboard can in some case damage
paintings, clocks, musical instruments, building components etc.
Further effects and consequences of high humidity is condensation behind
plasterboard walls that can result in structural damage and can provide
perfect conditions for the growth of mould and mildew.
Ideally during the winter months an office
should be about 22°C with a relative humidity between 30 and 60 percent.
During the summer months, an indoor temperature of about 20°C with a
relative humidity (UK) between 40 to 60 percent is considered normal.
Computers, office equipment and paper products can be adversely
affected by high humidity and shorten their life. A building
envelope and the heating ventilating and air conditioning (HVAC)
system must maintain proper humidity levels inside the building.
Mould and mildew will otherwise grow under inadequate conditions.
Maintaining positive internal building pressure and humidity levels,
below 60%, is essential to provide proper indoor air quality in
Exhausting air from rooms like toilets,
cafeterias and other areas without replacing it, creates a negative
pressure that draws unconditioned air through exterior walls,
windows and doors.
As the outside air is drawn into a
building by the negative pressure that is created by air movement or
exhausts, the moisture in the air may condense when it comes in
contact with the cooler surfaces. The condensation provides the
moisture fungi required for growth.
Mauve/black areas are dense
moisture or damp
Please call us at any
time for information on your specific requirements.