Few days back I noticed that the top portion of the ventilation area of my Bathroom has a gap, through which rain water could easily enter (as shown in the Image). I had previously applied Silicone sealant at the sides and the bottom, but that did not suffice. So I decided to seal the top gap with sealant. Here is an Instructable for all those who are facing the same issue. The directions remain the same for sealing applications in Doors, windows, glass partitions, etc.

Step 1: Things You Will Need

1. Silicone Sealant – either General purpose or Fungus Resistant Silicone Sealant. I chose Fungus resistant sealant, since the ventilation area is in constant touch with water / moisture and there are chances of Fungus buildup in the future – which I wanted to avoid

2. Dusting Cloth – to wipe and clean the surface

3. Sealant Gun

4. Cutting Tool / Cutter

5. Detergent / Liquid soap mixed in water – helps in removing unwanted or scrapped sealant from any surface or skin

6. Sealant Spatula (You can make it yourself or buy one from the market)

7. Tissue paper – To collect the unwanted sealant

Step 2: Preparation of Surface

Before applying the sealant I removed the exhaust fan, so that I could get access to the whole area. Then, I cleaned the surface thoroughly with a dusting cloth to ensure that there is no dirt or water accumulation near the area of sealant application.

PRO TIP: If you are planning to apply sealant during the monsoon, ensure that the area where the sealant will be applied is completely dry. If sealant comes in contact with water or wet area – the curing will not take place properly and also sealant will not bond well with the surface.

Step 3: Get the Sealant Ready

Cut the tip of the sealant plastic cartridge first using a cutting tool. Then place the plastic nozzle over the cartridge tip. Next step is to cut the tip of the nozzle at an angle of 45 deg. This helps in giving a good shape to the sealant when it comes out of the nozzle. Remember, the size of orifice / opening area at the tip defines the bead size of sealant that will come out of the bottle. You can cut the nozzle in two ways. I used the cutter which comes at the back side of the gun. It is simple this way, and gives me a proper shape. If this is not available in your gun, then do this with a cutting tool. When you are done, load the cartridge into the gun.

Step 4: Do This Before You Begin Sealing

Prepare a mix of detergent / liquid soap with water and keep it by your side. If you have a sealant spatula, dip it in the detergent solution. The purpose of the spatula is to give a uniform shape to the sealant after it is applied to the surface (will show it in later steps). I have made my own spatula using a Plastic ID card. You can do the same using an ID / bank card. Also keep some newspapers / tissue papers handy, so that you can remove the unwanted sealant from the spatula, surface, hands, etc.

Step 5: Apply Sealant

PRO-TIP: Before you begin applying, gently pull the trigger and bring the sealant to the tip of the nozzle. This way you know where the sealant is.

Bring the tip of the nozzle near the application area and slowly pull the trigger so that the sealant oozes out. Move the tip along the surface in a slow motion and keep pulling the trigger slowly, to get a uniform bead. This way, cover the whole area with sealant.

When you are done, release the back rod which is in contact with the plunger of cartridge. If you don’t do this, the sealant will continue coming out of the cartridge if left unattended.

Step 6: Give Shape to the Sealant

Use the spatula and move it in one direction over the area where sealant was applied. As you can see, the sealant now has a proper shape. Remove the unwanted sealant from the spatula with tissue paper.

If you do not have a spatula, dip your finger in the detergent solution first and then move your wet finger over the sealant, the same way you would do with a spatula. Do this as a last resort, because it is difficult to remove the sealant once it comes in contact with the skin, and you will need to wash your hands properly.

Step 7: Let the Sealant Cure

Ideally, the sealant cures within a day (24 hours). Ensure that the sealant does not come in contact with water and there is no physical damage to the sealant lining during this period.

THAT’S IT. The gap has been sealed. It’s been a few days since I have done this, and there has been no leakage from the ventilation area!!