You know how it is, somebody always telling you that what you have done is inadequate. I don’t know about you but I always prefer to know what people’s expectations are before I start a job. That way, I stand less chance of either disappointing them or being disappointed myself.
It is also confusing when different methods demand different products in order to fit the bill but you never quite know which to use in a given circumstance. There seem to be so many rules in respect of lintel bearings these days, but a good rule of thumb is that the pressed steel variety needs a 150mm bearing (or six inches in old money) while concrete or steel universal beams only need 100mm (four inches).
It is normal that the people who control our industry, approved inspectors, building control, etc. do look at this particular aspect of construction. It is important after all since the lintels we use and the steel support structures do transmit the building’s load to the ground and they do contribute massively to the safe building environment. They must however be installed correctly.
Top tips for lintel installation
Pressed steel lintels come in many guises and each surprisingly is different. It is normal for your local merchant to supply the type that they stock and the onus is on you to discover how they should be installed, whether a separate cavity tray is required, how they should be loaded and where they might require an intermediate support until the masonry being carried is able to contribute to the strength of the lintel. This last point may surprise you but read the manufacturers literature and you will find that some form of temporary support is often required and the masonry above really does form part of the lintel design.
So here we go. In line with normal practice I am in the process of putting on my parka with snorkel hood and I am about to spout the top tips for lintel installation: -
- Check the length of your bearing - 150mm is about right
- Ensure that your lintels are bedded on mortar for both the internal and external skins of the building
- Make sure that the lintel bearing is formed from a full masonry unit. Small pieces of poorly cut or poorly bonded masonry will not do and may be storing up trouble for you in the future
- Lintels should be laid level and true. They should be true in both planes and certainly not be allowed to lean into the building
- Some lintels have a protective coating that can be more easily damaged than others. If you damage a coating of any type (galvanised or painted) then you should make good prior to carrying on building. A damaged coating can seriously reduce the life span of a lintel to such an extent that it may not survive the ten year term of a MasterBond warranty
- Concrete lintels have to be laid the correct way up. Many have TOP written on them and you should not be able to read this from the underside of the lintel after installation (no, really!)
- Lintels should be positioned so that the toe is forward of any window or door frame. The toe is designed to shed water over the frame and prevent tracking. You have been warned!
- Cavity trays should always be used together with weep holes at approximately one metre centres, even if the manufacturer suggests that these are not required.
As a footnote, a lot of MasterBond warranty claims involve the ingress of water and a high percentage of these are due to lintel installation or lack of cavity tray work and weepholes. The construction is easy, you just have to get into the habit of thinking that the lintel has more than one role in construction; it also keeps water out of the building.
Enjoy your building, get your customers to buy MasterBond warranties and I’ll see you next time.