J is for… joists

J is for… joists

Every week we bring you the latest instalment of our A to Z of loft conversions, in which the technical elements become easier to understand. Today we’re on to letter ‘j’ and we’ll be talking about joists.

For those unfamiliar with the loft conversion process, it is one of the most effective solutions for creating extra space in a house, while adding the most in terms of your home’s monetary value.

But before you can give the go-ahead for a loft conversion, your existing loft will need to be inspected to ensure that it is structurally able to support a conversion. And that’s where the joist theme comes in.

There are two types of structures generally used for roof construction – traditional framed type and truss section type:

Traditional frame type
A common element of houses built pre-1960, the traditional frame consists of rafters and ceiling joists, along with supporting timbers, being cut to size before assembly. Giving the best structural support, this type of roof structure is often deemed the most suitable for loft conversions. By strengthening the rafters and adding in more support, it is relatively simple to open up the space and increase the size of the room.

Truss section type
Truss roofs have been used since the 1960s. The advantage of this roof structure is that it is very easy and fast to assemble as the majority of the work can be done in a day. There are of course a few setbacks – namely, the thinner, cheaper timbers used are not given any loadbearing structures underneath which means that it requires a lot more work to open up the space to be used as a room. If your house has this roof structure and you wish to convert the loft, it will be necessary to insert steel beams between the loadbearing walls. The new floor joists will then hand on to the beams to add further structural input. While it is possible to do this task before converting the loft in question, it is usual practice for it to cost more under this circumstance.

Do I need new joists?
Often, the existing ceiling joists will not be enough to support a conversion floor, which means that additional new joists will need to be installed in order to comply with Building regulations. A structural engineer will be able to specify the size and grade of the new joists to ensure that your home will be able to hold a conversion floor.

The new joists will be fitted between the loadbearing walls, alongside the existing joists. Where there is a window or door opening, thicker timbers will be used to reduce too much pressure being exerted on the opening lintel.

Once the work on the joists has been completed, the construction team will then be able to get on with the loft insulation (covered in last week’s post) and before you know it, your newly converted loft will be complete.

Here at Econoloft, we’ve been in the industry for over 40 years, making us something of an authority on the loft conversion process.

If you’re looking for inspiration, check out our gallery of previous client work.

For more information or to book your FREE estimate, contact Econoloft today on FREEPHONE 0800269765 or fill in a call back form and we will contact you when it’s convenient.