Can you lay loft insulation over joists?

If access is easy and your loft joists are regular, you can use rolls of mineral wool insulation. The first layer is laid between the joists – the horizontal beams that make up the floor of the loft – then another layer is laid at right angles to cover the joists and make the insulation up to the required depth.

Can I lay insulation on top of joists?

Joists tend to be only about 100mm high (although this can vary), so match the insulation thickness you buy with the joist height – once installed, the insulation should come up to the top of the joists. You will need to work the insulation around and over any downlight caps that may now be present.

Should attic insulation cover joists?

Always cover the tops of the ceiling joists to make sure the insulation is deep enough to reach your target R-value and to prevent thermal bridging, the heat loss that occurs through the wood framing.

Can I lay loft insulation on top of loft boards?

Yes you can most certainly overlay and additional layer of insulation over the chipboard. I would leave the insulation short at the eaves though to ensure there is adequate ventilation in the loft space. This would most certainly improve you homes thermal performance during winter months.

Should you insulate the underside of your roof?

In order to avoid damage to the roof deck, you should insulate ceilings to create an air barrier between the living space and an unfinished attic or airspace underneath the roof deck.

How to Insulate Your Loft | ADVICE | Homebuilding

Can I put insulation between roof rafters?

You can use rigid insulation boards, carefully cut to size, or you can have foam insulation sprayed between the rafters. Whichever approach you use, you will need a specialist professional to insulate your roof – this is not a DIY job.

Can insulation go against roof?

Attic insulation should not touch the roof. Although it can be tempting to over insulate, resist the urge. Too much insulation hinders airflow and can keep excess moisture from escaping, especially in attics.

Can I lay loft insulation over cables?

Yes, you absolutely can. You can lay insulation around the junction boxes as well. Making sure that the insulation is of a fiberglass material will not only ensure a fireproof setup but also reduce airflow from the home through the attic.

Can I insulate on top of floorboards?

If you are insulating an existing concrete floor, then insulation can be added over the top of the floor. If the solid floor is being removed or the project is a new build then it is possible to insulate beneath the solid floor.

Can I cover my attic insulation with plywood?

Once the insulation is down, you can turn your attic into valuable storage space by covering the floor with plywood. It will also make the attic a safer place in which to walk.

Can I run insulation perpendicular to joists?

Enhance Existing Insulation

Just remember to run it perpendicular to the joists. You can also top off existing insulation with loose fill fiberglass or cellulose, but fiberglass or mineral wool batts are easier and neater to install.

Should I insulate attic roof and floor?

roof insulation is no-contest. The floor wins every time. Insulating the floor is standard practice for an unfinished attic space. The exception to this rule takes place when families opt to convert an unfinished attic space into something usable or livable.

How should insulation be installed in the attic?

You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.

Can you over insulate a loft?

As long as you ventilate your property properly, you can have as much insulation as you like within reason. The trick with loft insulation is to balance the amount of insulation you have with the amount of ventilation necessary to prevent damp. As long as you get that balance right, you should be fine.

Should loft insulation be pushed up to the eaves?

Don't pack it in: squashing insulation to fit the space seriously compromises its effectiveness. Also avoid pushing the insulation into the eaves to keep ventilation paths at the edge of the roof well aired and roof timbers dry.

Does squashing insulation stop it working?

Can cause damp – as standard boarding is placed onto the joists of your roof, this will inevitably squash your insulation, which stops it from working and will cause condensation to build up as it doesn't have room to breathe.

Should you insulate floor joists?

Insulating the joists can help create an effective vapor barrier that will keep humidity from sneaking inside your basement and causing the joists to expand and contract. This can be beneficial if you have hardwood floors and are all worried about moisture seeping up from the panels due to bad insulation.

Should wiring go over or under insulation?

So what's the correct way to install loft insulation? All electric cables need to be in free air above the insulation, and well clear of any flooring above.

Can junction boxes be covered with insulation?

“Junction boxes can be covered by insulation in such a manner that it can be removed without damaging it to access the box. Foamed-in-place insulation isn't removable and therefore not permissible.”

How much space do you need between roof and insulation?

1 address the requirement for a minimum 1-inch clearance between the insulation and sheathing to provide proper airflow. Note that most building scientists will recommend at least 2 inches of clearance for best performance (i.e., more than the code minimum).

How much space should be between ceiling and roof?

Builders aren't bound by standard rafter spacing measurements. But they do tend to space rafters in one of several industry-standard increments, typically either 12, 16 or 24 inches apart.

What are the building Regulations for loft insulation?

Since 2003, current building regulations recommend a depth of at least 270mm (mineral or glass wool) in the loft – use this as a starting point rather than a finishing line to see larger savings. In 1995, the recommended depth was 200mm. Prior to that it was less than 100mm.