Warning: Read through everything before starting! Some parts have a long lead time and you do not want open holes in your wall while you wait for delivery!
These are the vent covers we replaced the existing ones with. They are delivered from China so take a few weeks to get here. Read on for more details.
Most new houses are A rated. However there are holes in the envelope of the house in the form of air vents. These are there to ensure a constant flow of fresh air.
NOTE Vents are there for a reason. Blocking them up or closing them off is not recommended without understanding the impacts and how to adjust for them (e.g. regularly open windows instead, even in winter).
If the house was fully sealed (e.g. passive standard) then without some kind of vent, the air would quickly become stale and build up smells and other things. In passive houses this is solved with mechanical heat recovery ventilation. In non-passive houses we just have vents. Vents are actually just holes through the wall, with some plastic cover that prevents larger items from entering, but does not impede the air flow at all. On warmer days, this is fine. On cold days or in the winter it makes it near-impossible to heat the house.
So I set about finding some alternative. Mechanical heat recovery ventilation systems can be expensive and require construction changes for installation. Instead, how about we just change the vent covers so that we can open and close them as we like?
This is how I did that for our house.
I replaced the existing vent covers with new ones that allow us to adjust the air flow manually as we like so that inb the winter they can be closed up a bit, or in the summer they can be wide open.
In our house the current vent covers are circular covers that have two pieces of spring metal on the rear that are supposed to hold them into the vent hole. These two pieces of metal are invariably not up to the job. It seems that to help with this the builders have pushed the covers into the wet plaster skim and the painter has then painted up over the edge of them. Thus when the plaster (and paint) are dry, the rim of the covers are inside the surface of the wall finish, holding the covers close to the wall.
This means that they need a little bit of force to remove. I suggest to try this with only one vent first until you see what you have behind it.
To get each cover off, I inserted a flat blade screwdriver under the inside edge of the circular rim of the cover and levered the vent away from the wall.
I check that I can get the cover off without too much hassle and what the wall looks like after I've done so.
I can see that there is a ring of plaster skim and paint torn away with the rim of the cover.
We'll need to repair that later on, For now we can push the old cover back in.
With the cover off I can see that the vent holes were constructed by either drilling a hole through the wall, or leaving a gap when constructing the wall, and then inserting a piece of 100mm (4") pipe that traverses the width of the wall. The plaster then finishes up over the ends of the pipe.
For each vent I check:
- The internal diameter of the pipe is indeed 100mm (4"), as this will affect the size of replacement cover that will fit
- The opening in the plaster is also 100mm (4") in diameter, and concentric to the pipe. Here I find that the plaster obstructs the opening for some of the vents holes around the house. Because of the type of covers we will use to replace the old covers we'll need to widen the holes to all be 100mm (4") diameter before we can insert the new covers.
- The clearance around the hole is at least 25mm (1"). I find that the vent hole in the living room is too close to the ceiling to allow the needed clearance for the replacement vents, so we will not be able to replace this one with this method.
Checking these for each vent I find that:
- The opening in the plaster will need widening for most of them before the replacements will fit
- The vent in the living room is too close to the ceiling to allow the needed clearance, so we will not be able to replace this one with this method.
For most of these items I have indicated where I found these available. But any good hardware should have most if not all of these.
- Pencil
- Stepladder - to safely reach the vents
- Dust sheet
- Cold chisel
- Available from Woodies
- Lump hammer / stone hammer
- Filler
- I used Everbuild One Strike Filler as it is good for a sanded finish on thin applications, which is what we'll need.
- Available from Brady's of Greystones
- Filler blade
- Available from Brady's of Greystones
- Fine/Medium sanding block or paper
- Face masks - to prevent inhalation when sanding
- White matt ceiling & wall paint
- Available from Woodies
- You'll likely need only a small amount of this, less than 1 litre, but we could only find 2.5 litre pots in our local Woodies
- Replacement vent covers
- Ordered online from Fruugo
- For 100mm vent holes with the plain solid face, I ordered the "10CM A" variant
- These took around 2 week sto arrive, but can take longer
Once I had all the tools and parts, this process took me the better part of a day, including time to allow the filler to dry.
while I waited for the filler or paint to dry on one vent, I moved forward with work on another vent. This meant moving the ladder and dust sheet around the house a lot, but it resulted in a shorter time to get finished than otherwise.
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Lay down the dust cover, ensuring it is flush to the skirting board near to the vent. The aim is to avoid filler or paint getting stuck into the carpet, and to make cleaning up easier after the work is finished.
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Stand the stepladder on top of the dust cover, facing the wall, below the vent.
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If not already done, remove the existing vent cover as described previously.
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Remove the screw in cover face from the new vent cover, by unscrewing it all the way out. This allows a good view of any blockage during the next steps.
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Offer up the new vent cover to the wall, ensure it is concentric to the pipe, and assess the fit.
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If there is any blockage by plaster:
6.1. Use the pencil to mark around the outside of the rear part of the new vent cover that will fit inside the hole.
6.2. Use the lump hammer and cold chisel to knock away any part inside the pencil mark.
Be very careful the plaster board will want to come away in large chunks. Instead, try to chip away small amounts until you reach the needed size.
6.3. As you remove plaster, offer up the new vent cover again to check if the hole is large enough and still concentric to the pipe.
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Sand the surface around the hole to ready the surface for filling. Include the area where any paint was damaged while removing the old vent covers.
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Use the blade to apply the filler so as to fill any recess created when removing the old vent cover. The recess is quite shallow but can be visible across the room by the slight shadow it leaves if not taken care of. Apply the filler relatively generously so as to ensure good coverage to at least the same level as the rest of the wall.
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Let the filler dry for at least 30 mins - 1 hour, but the longer you can leave it the better.
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Sand the filler down flush with the rest of the wall, ensuring any high spots or rough spots are sanded level.
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Paint the new surface. The repaired surface should now be indistinguishable from the rest of the wall. Depending on the paint this may require a couple of coats.
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When the paint is dry, push in the the new cover and screw the cover face back in.
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Gather up the dust cover with any debris to empty into an appropriate waste bin.
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Vacuum up anything that made its way past the dust cover. Be sure to check the skirting and any window sills or architrave for stray lumps of filler.
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Stand back and marvel at you workmanship!