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We had our house re-roofed a few weeks ago and I noticed that my attic is more drafty.

I live in the UK and my house was built in the 1960s. It is a semi-detached bungalow.

I'm not sure what the old underlay was, but it was pretty heavy duty looking. It was a black rubber / plastic kind of material.

The roofer installed Protect VP400 Roofing Underlay with Redland Double Roman 50 tiles and semi round Redland ridge tiles. He replaced all the battens.

It's quite stormy here at the moment and I noticed more of a draft in the attic. More so than before the new roof. I checked around for light coming through but there was none. No leaks that I could detect.

Any ideas if this is normal and the result of a more modern roofing system or is there a problem with maybe some loose tiles and the underlay is preventing rain from getting in?

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  • I know nothing about roofing in the UK, but "ridge vents" are a popular thing where I'm at. It's a special device that goes on the ridges of the roof to turn them into a vent leading to better air flow. Is it possible some new venting tech was added with the new roof?
    – JPhi1618
    Commented Sep 4, 2019 at 17:57
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    Hello, and welcome to Home Improvement. It's unlikely that the breeze is going through the roofing material; as @JPhi1618 says, it's probably something else. And, you should probably take our tour so you'll know how best to participate here.
    – Daniel Griscom
    Commented Sep 4, 2019 at 18:00
  • More drafty is generally good in an attic (to a degree). Do you have specific concerns other than potential water leaks?
    – isherwood
    Commented Sep 4, 2019 at 19:26

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In the 60’s all the roofing I put down we used roofing felt 90 lb per roll. Some people call tar paper it is heavy and black and makes a good barrier. I would be guessing since we don’t know what your original vent system was or is now, but with some homes we did just prior to my knees saying no more roof jobs we had to add vents or a complete ridge vent this may be the reason you feel more drafts in the attic but air movement is needed to extend the life of the roof and the structure. New venting may be the same but you just happen to notice because you just had work done and there is bad weather. I would say if you don’t have leaks don’t worry about it.

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Each roofing manufacturer requires a certain amount of venting per square foot of roof area for their product to perform best.

You can read on the shingle wrapper how much is required and most roofers will automatically add the required number of vents.

The Building Code also requires a minimum of 1/150th the area for ventilation. (See ICC R806 Vents.)

However, there is one exception: The attic ventilation can be reduced to 1/300th the area to be vented provided one of the following items are met:

1) a Class I or II vapor retarder is installed on the “warm-in-winter” side of the ceiling, or

2) not less than 40% and not more than 50% of the ventilation is located in the upper portion of the attic. The upper portion is defined as: “Upper ventilation shall not be lower than 3’ below the ridge or highest point of the roof. “ (See ICC R806.1.2.) Maybe they added vents to meet this requirement.

So, you can see there is clearly a benefit to having ridge vents, gable vents, etc. , but in a proportion that allows COMPLETE CROSS-VENTILATION to the attic.

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