how to dry out condensation in a loft

How To Dry Out Condensation in a Loft in 6 Easy Steps (DIY Guide)

Knowing how to dry out condensation in a loft will save you a world of pain further down the line. I’ve renovated several houses over the years, and whenever I encounter condensation in the attic, like all good detectives, I search for the usual suspects. 

Tools and Materials

Before we get down to the details, we must gather the right tools and supplies. Luckily, drying out wet loft spaces is relatively simple (in most cases).


  • Dehumidifier.
  • Ladder.
  • Face mask.
  • Gloves.
  • Torch.
  • Damp meter.
  • Tape measure.


  • New loft hatch (or sheet of MDF).
  • Wooden battens.
  • Air vents.
  • Bathroom extractor fan.

How To Dry Out Condensation in a Loft — Step-by-Step Instructions

1: Inspect the Loft Space

To determine how wet your attic is, don your face mask and gloves and climb into the roof space. Why face mask and gloves? Loft spaces are full of insulation, which can irritate your lungs and cause skin rashes. 

Luckily, modern and more user-friendly insulation materials are available these days, but older houses will likely have a thick layer of fibreglass insulation, so be careful. 

Use your ladder to access the loft, taking care to move the hatch. Once inside, take extra care to stand on the beams rather than the insulated sections in between. Additional ventilation is vital to solving the condensation problem, but putting your foot through a plasterboard ceiling is not the answer. 

Hopefully, you have a boarded loft because it’s a great place to store everything from Christmas decorations to old suitcases and boxes. 

Use the torch and crawl into the corners and narrow sections to see if the air vents are blocked. Building regulations dictate that houses have two opposing vent slots in the roof to allow moisture to escape and air to flow.

With any luck, this is the cause of your moisture problem and is easy to fix. Use your moisture reader to check wooden rafters for damp levels. 

2: Install a Dehumidifier

dehumidifier's option

Dehumidifiers remove excess moisture from the air, making an enormous difference if you have a condensation problem. Place the dehumidifier in a central location with good airflow and zero obstructions. 

The good news with a dehumidifier is it’s easy to use, cheap to run, and effective. The bad news is it doesn’t get to the core of the problem. If you’ve got a condensation issue, you should deal with it, so think of the dehumidifier as a temporary solution. 

Place the dehumidifier in a central location in your attic. Alternatively, stand it in a communal area inside your home to reach all corners of the house. 

A dehumidifier works better in developed loft spaces because, in undeveloped attics, it draws moist air from the outside through the vents. 

3: Set Up a Fan

Increase airflow in the loft by using a desk fan. You can set up two or three fans to circulate the air for maximum efficiency. If you set the fans up in conjunction with the dehumidifier, it helps to distribute the dried air. 

4: Fit a New Loft Hatch

Your attic space is cold and unheated, and insulation is a barrier between the heated building below and the roof above. One of the significant causes of loft condensation is an ill-fitting loft hatch. 

Your roof space is designed to be cool to act as a barrier between the changing temperatures outside and the heated indoor spaces. When heat meets cold air, it creates vapour, and your loft becomes damp. 

Grab a torch, place it in the loft, and shut the hatch. If you can see daylight, your hatch doesn’t fit snugly and will let moisture into the attic. In this case, a new, snug-fitting loft hatch will reduce moisture levels created by human activities, stopping leakage into the loft.

You can make a new loft hatch from scratch by cutting a square of wood or MDF (medium-density fibreboard) to size and attaching insulation to the back. Always measure from the inside lip of the opening so that the edges overlap to hold it in place. 

Pro Tip: MDF is a light material, so it might be worth attaching a couple of wooden batons to give the hatch the weight it needs. It helps to seal the loft access and stops the hatch from banging when the wind picks up. 

If your DIY skills don’t stretch to making a new loft hatch, check out Rated People to find a trusted professional in your local area. 

5: Install a Bathroom Extractor Fan

installing bathroom extractor fan in white ceiling

Your bathroom is one of the dampest parts of your home. Bath and shower steam escapes and penetrates through leaky loft hatches, light fittings, and even ceiling holes where there are cables and wires. 

Installing an extractor fan on an outside wall, window, or ceiling creates an outlet for the damp air and reduces moisture penetration in your loft. However, when moist air passes through cold areas like your attic, you’ll need a condensation trap to catch inevitable water drips.

So, when you install your bathroom fan, check out our article on how to fit a condensation trap for the latest tips. 

If your budget doesn’t stretch to an extractor fan, installing simple air vents in your window frames makes a difference to condensation levels. Keep the vents open when you shower or bathe to let the moisture escape. 

Pro Tip: The cheapest option for installing an extractor fan is locating it on an outside wall. If you vent it through the ceiling, you’ll need a roofer to ensure the ducting and outside vent are correctly fitted.

The video below gives some great instructions on fitting a bathroom fan: 

YouTube player

6: Improve Insulation

unfinished loft insulation

Another reason why you have condensation in the loft could be insufficient insulation. Insulation creates a barrier between the warm air inside your home and the cold roof space. If you have inadequate insulation, moist air finds its way into the roof void, reacting with the cold air. 

When that happens, vapour converts to water, and you get (you guessed it) condensation. Luckily, upgrading old loft insulation is a simple task and not very expensive. This Rockwool Insulation Roll is affordable and readily available, and it’s also easy to fit because you can cut it to any size. 

The upside of improving loft insulation is you retain heat better, lowering your energy bills, which is fantastic for your wallet and the environment!

For more tips on installing loft insulation, check out the video below from Homebuilding and Renovation:

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Other Tips to Reduce Condensation

Knowing how to dry out condensation in a loft is crucial because it minimises mould growth, which protects woodwork and other structural elements. However, you won’t eliminate all condensation because everything we do creates moisture.

Every time you breathe, wash, cook, or even sweat, it raises the moisture levels inside your home. If there’s no outlet for the wet air to escape, it circulates until it finds a cold surface to settle. 

If you have condensation in the loft, you might have a moisture problem in other parts of your home. Built-in wardrobes are another area where damp air likes to gather. Check out our article on how to stop condensation in built-in wardrobes for pro-level tips. 

Loft insulation effectively stops this leakage, but you can close off the other avenues of escape by taking the steps outlined above. However, there are some minor changes you can make to help. So, what are they?

Put Lids on Pans

Your bathroom is one of the wettest rooms in the house, but what about your kitchen? Look at your windows when you boil rice or pasta without a lid. If it’s cold outside, the steam clings to the glass.

Boiling food with a lid on the pan restricts moisture from rising throughout the house and reduces condensation in the loft. 

Bathe With the Door Shut 

At the very least, close the bathroom door and shower with the window open to let the steam out. The more steps you take to limit moisture build-up, the better you can control condensation.

Leaving the door open allows vapours to travel to the coldest spots in the house and cause condensation. 

Don’t Dry Clothes Indoors

woman hand hanging clothes

One of the most significant ways to increase moisture inside your home is to dry laundry on an airer or the back of a radiator. The air becomes wet as the clothes dry, and you get condensation problems. 

If you must dry clothes inside, close the door so that other rooms are not affected and always open windows to get good airflow. 

Vent Your Tumble Dryer

If you live in a flat or a house without a garden, drying clothes indoors is your only option. However, there are measures you can take to reduce moisture. I.e. ensure you vent your dryer through an open window or an exterior wall. 

Inspect the vent to keep it clear from blockages and dust build-up that might restrict airflow. 

Reduce Storage in the Loft

Your loft is not designed to be a storage area. By reducing the amount of stuff crammed into your attic, you can increase airflow (which is what it’s for) and reduce condensation. 

Furthermore, filling your roof space will damage the items inside the boxes because damp air encourages mould growth, which attacks everything. So, if you have a moisture issue in the loft, maybe it’s time to gather up all your boxes and have a car boot sale. 

Wipe Condensation Away

When you see moisture settle on walls and windows, grab a towel and wipe it dry. If you leave it to sit, the air becomes wetter, and your condensation worsens. It also creates the perfect environment for mould and mildew growth.

Use Kitchen Extractor Fans

Run your kitchen extractor fan while you cook food on the hob. It extracts wet air and also removes food odours. 

To extract all the moist air, let it run for 20 minutes after you finish cooking. Also, close the kitchen door to restrict the wet air to one room. 

Final Thoughts

Excess condensation is your enemy, as moisture is a breeding ground for mould and mildew. And once it takes hold, it can be difficult to remove. It pollutes indoor air, damages the structural elements of your house, and creates foul odours. 

Whenever I advise on how to reduce condensation, I always start with the most obvious solutions and then focus on what you can do in your everyday life. Cooking with lids on pans, opening windows, and improving ventilation are small changes with maximum impact.

If you lack the skill or desire to perform a condensation investigation, visit Rated People to find local damp specialists in your area. 
For more information on controlling condensation, check out our damp proofing cost guide.