10 x Felt Lap Vents Prevents Loft roof Condensation. Attic Space Ventilation

Product Information

I have found quite a few spots where there isn't any insulation at all so I've already gone through 2 rolls of the 100m base layer just getting it ready for today. Roof ventilation from Manthorpe can help save both pennies and the environment. In an increasingly energy-conscious world, clients are much more aware of how to save money as well as the planet, so specifications can become even more demanding, putting extra pressure on budgets. Fortunately, Manthorpe’s cost-effective solutions cater for all types of roof ventilation requirements, including new build and refurbishment. The Hambleside Danelaw underlay lap vent has a shallow and tapered design to fit between the overlaps in the roofing underlay below the tiles or slates to introduce ventilation openings. An ideal part of this type of ventilation is that little to no maintenance is required. However, if applied with sand and mortar, they need to be replaced with mortar bonds. We have moved into this house a couple of years now and we are having a lot of problems with the heating. Changed to gas after the first year and fixed some of the plumbing issues but we are getting a lot of condensation, mould on some of the ceilings in the corners and the house doesn't really retain any heat.

At this point (called the eaves) there should be a gap between the underside of the roof and the outside wall. This gap should be about 50 – 75mm wide and will usually have a meshed grill within it stopping insects and birds getting in.Usually fitted retrospectively to properties with additional loft insulation recently installed, however the Felt Lap Vent will help to combat the problem of condensation build up in any roof space with a lapped felt/membrane construction.

It is recommended that one ventilator panel is fitted between each rafter in the lowest underlay lap above the level of the insulation layer in the loft on both sides of the roof (see product brochure fig. 1). Typically a leak will usually have an evident external cause and be localised whereas condensation will be across the whole roof space.This type of vent may also be referred to as an eaves vent. These vents can be found installed in many modern houses and are typically built into the soffit. The result is continuous 10 – 25 mm ventilation at a low level around the eaves of a property. Side view on a felt lap vent separating the roofing felt to increase air flow – Image courtesy of Manthorpe On a cold day there will be condensation on the roof felt – this will be droplets running downs the underside of the roof felt The Manthorpe Felt Lap Vent is a refurbishment product designed to increase the amount of ventilation into existing roof spaces. We are quite used to seeing condensation in the bathroom, firstly in the form of hot steam as we shower or bathe, but then, as the bathroom cools, the steam condenses on the ceiling, cold water pipes, tiles etc. It is not so obvious in the loft.

This then means that your roofs free air flow (80,000mm2) divided by a ridge vents ventilation capacity (12,000mm2) would suggest 6.666 vent tiles, so you would need 7. You can find many roof tile vents here, including double Roman, roll and more. Each offers a style of ventilation to suit as much or as little as you need. The vast majority of lofts or attics in this the United Kingdom are cold roofs, and this is where condensation will occur. It is not likely to occur in warm roofs and if it does there will be other steps to take. How to Ventilate a Loft or Attic to Prevent Condensation Alongside the tile and slate vents, Danelaw offers a range of eaves and soffit vents, CON6+ and CLAY6+; the ventilated dry fix ridge and hip systems. By the time that you have completed all these measures you should have enough ventilation in your loft of attic space to stop condensation forming but it pays to be sure. F you need to go to the expense of getting a roofer to fit vent ridge it pays to make absolutely sure you have enough. That said, too many is not helpful as they are awkward to remove should you need to.Wall vents that provide air to a room with heat-producing appliances (e.g., gas appliances or central heating boilers). It can be hard to tell if it’s condensation or the roof is leaking, particularly as it can be astounding how much moisture can condense in the right (or should we say, wrong) conditions. Danelaw® offers a wide range of roofing ventilation products covering a wide range of tile types and construction details, from new build developments to refurbishment. If you are suffering from condensation in your loft it will be a “cold roof”. This is the most common type of roof with a loft or attic. So, for example, if your roof is 8m long, you would need 8m (=8,000mm) multiplied by 10mm =80,000mm2.