Technical Advice Page

Technical Answers to some of your questions

	Chases in walls Care should be taken when cutting vertical and horizontal chases in walls if the structural stability is to be maintained. The depth of any chase shown should be limited as listed below. A chase is a recess, cut or built in a wall, inside which small service pipes are run and then covered with plaster or walling.	Chimney Cowls The cowl, usually made of galvanized iron, is fitted to the chimney pot to prevent wind blowing the smoke back down into the room beneath. They have been in use for centuries.
Chimney stack removal guidance Most older houses were constructed with fireplaces in every room to provide heat. These days central heating has replaced the need for fireplaces and the chimney breast is seen as wasted floor space in the room. Although a fireplace does provide a focal point in the room, the removal of the fireplace and the chimney can increase the size of the room significantly.	Domestic Ceiling Joists Sizes When sizing the timbers within the ceiling it is important that the correct size of joists are used.	Disabled Access Disabled people shall have access from the point of entry to the principal entrance of a dwelling or the common entrance to a block of dwellings by
Chimney Cap Left uncapped, disused chimneys are prone to a number of major problems arising from exposure to the elements and blockage by nesting birds.	Domestic Floor Joists Sizes When sizing the timbers within the floor it is important that the correct size of joists are used.	Gas Flue Outlet Positions The correct positioning of gas flue outlets are important if the flue is to work properly.
Laying Cushioned Vinyl Flooring Our guide to laying cushioned vinyl flooring will help you archive the perfect floor finish.	Limiting Height of Chimneys and Parapet walls Where a chimney is not adequately supported by ties or securely restrained in any way, its height H when measured from the highest point of intersection with the roof surface, gutter etc. should not exceed 4.5W, provided the density of the masonry is greater than 1500 kg/m3	Notches and Holes in Joists Notches and holes are often required to be made in timber floor and roof joists to accommodate waste pipes from sanitary fittings, pipes for central heating installations or pipes and cables for other types of appliances.
Septic tanks and cesspools A cesspool is a large holding tank into which all the sewage from a building drains. It holds both solid waste and liquids and therefore needs to be emptied on a regular basis by a tanker lorry.	Domestic Stair Design Guide The clear, or effective, width of a stair should allow users to move up and down unhindered and, on stairs giving access to a dwelling or domestic building, permit people to pass on a flight.	Truss Rafters There are many different designs for truss rafters all have their purpose and advantages.
Ventilation of rooms The correct ventilation of a room is important if condensation problems are to be avoided. The guide below gives the minimum requirements for each room type.	Window Replacement Windows are functional items in dwellings providing weather protection, ventilation, day light and sometimes structural support.	Drainage Pipes Drainage pipes come in many sizes and materials. Pipes should be sized for their purpose.

Please check with your local building control department before using information contained in this page to ensure that they comply with your local building codes.

If you have any technical questions about your next home improvement project, please email us with any questions you may have at info@carryduffdesigns.co.uk

Full copies of the latest building regulations can be found here