Will a PIV system get rid of my mould problem?

In the majority of cases, yes. Where mould is caused by condensation resulting from inadequate ventilation, a correctly specified and installed PIV system will resolve the problem by maintaining a positive pressure within the property and continuously diluting moisture-laden internal air with fresh filtered air. However, where mould is caused by penetrating damp, rising damp or a structural defect, the underlying cause must be addressed first. We will always survey the property before recommending a solution.

Do I need building regulations approval for a ventilation installation?

Replacement of like-for-like extract fans in existing dwellings does not generally require building control notification. However, new ventilation systems — including PIV, MEV and MVHR installations — may be notifiable under Approved Document F, particularly in new-build or change-of-use projects. Any associated electrical works are notifiable under Part P of the Building Regulations. We will advise you on what applies to your project before works begin.

How long does a PIV installation take?

A standard domestic PIV installation typically takes half a day to a full day, depending on the property layout and the location of the unit. The installation is minimally disruptive — the unit is mounted in the loft or a central hallway, and a single diffuser is fitted in the ceiling below. There is no requirement to vacate the property.

Can ventilation works be combined with damp proofing or renovation works?

Yes — and in many cases this is the recommended approach. Ventilation is frequently specified as part of a damp proofing programme to prevent condensation from recurring after treatment. As a multi-discipline contractor, we can carry out damp proofing, plastering, decoration and ventilation installation as a single coordinated programme of works, with one point of contact and one programme throughout.

Our Services / Ventilation

Ventilation

Professional ventilation installations and Positive Input Ventilation (PIV) systems for residential and commercial properties across the UK.

Poor ventilation is one of the most common and most overlooked causes of condensation, mould growth and poor indoor air quality in UK properties. At 3T Restoration Ltd, we design and install ventilation solutions that address the root cause of these problems — not just the symptoms.

Our ventilation installations are carried out by experienced operatives and comply with Building Regulations Approved Document F (Ventilation) and the relevant British Standards. Whether you require a Positive Input Ventilation (PIV) system for a domestic property, a whole-house mechanical ventilation solution, or targeted extract ventilation for bathrooms and kitchens, we will specify and install the right system for your building.

Ventilation works are frequently recommended following damp proofing or remedial works to prevent condensation from recurring. As a multi-discipline contractor, we are well placed to carry out ventilation installations as part of a wider programme of remediation and renovation works, ensuring a fully coordinated and effective outcome.

Ventilation systems we install

The right system for your property

PIV

Positive Input Ventilation

A PIV unit is installed in the loft and gently introduces fresh, filtered air into the property from a central ceiling diffuser. This creates a slight positive pressure that pushes stale, moisture-laden air out through natural gaps in the building fabric — the most cost-effective solution for condensation and mould in most homes.

MVHR

Mechanical Ventilation with Heat Recovery

MVHR systems simultaneously extract stale air and supply fresh air, recovering up to 90% of the heat from the outgoing air stream before it is exhausted. Ideal for new-build and highly insulated properties where energy efficiency is a priority alongside air quality. A full duct network serves all habitable rooms.

MEV

Mechanical Extract Ventilation

A centralised MEV unit continuously extracts air from wet rooms — bathrooms, kitchens, utility rooms and WCs — via a network of ducts to a single fan unit. Running continuously at a low background rate with boost capability, MEV provides consistent whole-house extraction without the noise and on/off cycling of individual room fans.

Wall-mounted extractor fan with ventilation grille installed in a bathroom

Extractor fans

Individual Room Extractor Systems

Intermittent extractor fans installed in individual wet rooms — typically bathrooms, shower rooms, kitchens and WCs — provide targeted extraction at source. Modern units include humidity sensors, overrun timers and quiet DC motors. We supply and install fans compliant with Approved Document F minimum extract rates and Part P electrical regulations.

Ventilation systems we install

— Positive Input Ventilation (PIV)

PIV systems are the most widely specified whole-house ventilation solution for existing UK dwellings. A unit installed in the loft space or a central hallway draws in fresh, filtered air and gently pressurises the property, displacing stale, moisture-laden air through natural leakage paths. PIV is highly effective at eliminating condensation and mould caused by inadequate background ventilation, and is suitable for the majority of residential properties. Units are low-energy, quiet in operation and require minimal maintenance.

— Mechanical Extract Ventilation (MEV)

Continuous mechanical extract ventilation removes moisture and pollutants at source from wet rooms — bathrooms, kitchens, utility rooms and WCs. MEV systems operate continuously at a low background rate and boost automatically when humidity or occupancy increases. They are particularly effective in flats and properties where loft-mounted PIV is not suitable.

— Intermittent Extract Fans

Where targeted extract ventilation is required in individual rooms, we supply and install high-quality intermittent extract fans with humidity sensing, timer overrun and, where required, heat recovery. All fan installations comply with the minimum extract rates set out in Approved Document F and are tested on completion.

— Whole-House Mechanical Ventilation with Heat Recovery (MVHR)

For new-build properties and deep retrofit projects, Mechanical Ventilation with Heat Recovery (MVHR) provides a controlled whole-house ventilation strategy that recovers up to 90% of the heat from extracted air. MVHR systems are designed to meet the requirements of Approved Document F and Approved Document L (Conservation of Fuel and Power) and are increasingly specified in high-performance and low-energy buildings.

— Background Ventilators & Trickle Vents

Where background ventilation is insufficient, we install or upgrade trickle vents in windows and background ventilators in walls in accordance with Approved Document F. This is often the most cost-effective first step in improving ventilation in properties where condensation is a recurring issue.

Our installation process

Survey & Diagnosis

We carry out a thorough assessment of the property, including a review of existing ventilation provision, moisture levels, building fabric and occupancy patterns. This allows us to identify the root cause of any ventilation-related problems and specify the most appropriate solution.

System Design & Specification

We design the ventilation system to meet the requirements of Approved Document F and the relevant British Standards, taking into account the size, layout and construction of the property. We provide a clear written specification and quotation before any works commence.

Installation

All installations are carried out by our experienced operatives to a high standard. We minimise disruption to the property and ensure all penetrations through the building fabric are correctly sealed and weatherproofed. Electrical connections are made by a qualified electrician and all notifiable works are certified.

Commissioning & Testing

On completion, all systems are commissioned and tested to confirm they are operating within the design parameters. For MEV and MVHR systems, airflow rates are measured and balanced in accordance with the manufacturer's requirements and Approved Document F.

Handover & Documentation

We provide full handover documentation including system details, commissioning records, maintenance requirements and any relevant certificates. Where works form part of a wider remediation programme, ventilation documentation is included in the overall project handover pack.

UK building regulations & standards

All ventilation installations carried out by 3T Restoration Ltd comply with the following UK building regulations and standards:

Building Regulations Approved Document F — Ventilation (2021 edition)
Building Regulations Approved Document L — Conservation of Fuel and Power
BS 5250:2021 — Management of Moisture in Buildings
BS EN 13141 — Ventilation for Buildings: Performance Testing of Components/Products for Residential Ventilation
BS EN 15665 — Ventilation for Buildings: Determining Performance Criteria for Residential Ventilation Systems
CIBSE Guide A — Environmental Design (internal conditions and ventilation rates)

Frequently asked questions

Get a no-obligation quote

Contact us today to discuss your ventilation requirements. We will survey the property and provide a fully itemised, no-obligation quotation.