Professional Roofing throughout the NY Area

How Do You Stop A Flat Roof From Leaking

January 12, 2023
Spread the love

Flat roofs are common in commercial and industrial structures, but in recent years, homeowners looking for elegant and space-saving roofing options have discovered this roofing design appealing. Low-sloped or flat roofs provide a handy location for HVAC system installation and make roof repairs and maintenance straightforward. However, when your flat roof begins to leak, it is not good news. You should do a comprehensive assessment to locate the source of the leak and call a skilled roofer to do repairs to avoid water and moisture from producing problems including flooding, rotting, and mold development. The first step in repairing a flat roof leak is determining where the water is entering. Unfortunately, wetness inside does not always correspond to the roof region directly above, but might instead come from a problem location a significant distance away.

Some of the most popular areas to search for leaks are as follows:

  1. Splits and cracks

The material is not capable of properly expanding and contracting due to ageing, resulting in the material breaking since the expansion is more than intended.

  1. Overlaps and Joins

The lack of a good overlap is a typical reason of joins and overlaps leaking. Water then tracks in between the two layers as a result of this. It is normal for this to be a source of worry if the product has been heat welded together. The connection may fracture if it is not adequately welded. However, the material may split as a result of being weakened as a result of overheating the join and damaging/melting the substance.

  1. Around vents and roof lights

A typical problem is that the flange surrounding a vent is either too small or too close to the pipe or vent. It might also be due to improper installation or not being sealed to the flat roof material.

  1. Bars with Glazing

Old glass was usually fitted and sealed with putty, which not only becomes brittle with time, but also gradually loses its adhesive power.

Furthermore, flat roof leaks might be caused by rotting/old timber.

  1. Ridge Caps / Gone Infills made of foam

Foam infills used to fill gaps, notably on corrugated roofing, degrade (mainly due to UV deterioration) over time and fall out. It can also be pecked/removed by birds, eaten by insects and rats, and the 'remainder' will ultimately fall out.

  1. Angle shift, notably at a 90-degree corner / bend

It is important to check these areas as the ridge or curvature places different stresses on the roof material. This is common when lining gutters, covering asbestos sheets, or where the perimeter of the flat roof meets with a vertical wall. The 90-degree angle should always be evaluated first since cracking commonly occurs along this angle.

  1. Bolt and screw holes

There should be no bolt holes or screws running through any flat roof material, however due to the installation of air conditioning units, railings, and other fixtures, the silicones and mastics harden, leading them to fail in their ability to expand and contract enough.

  1. Walls with parapets

Weathering causes the top of the brickwork to degrade and break down. If the brickwork has been covered with a concrete or stone coping, it is critical to inspect the coping's attachment to the brickwork. You may discover a fracture between the coping and the brickwork, allowing water to track beneath. Water can then make its way into the hollow and finally show up inside the building - and this can be one or two storeys.

How To Stop Leakage

Repairing a flat roof leak can vary from an easy DIY job, to a large-scale project that needs expert help. The first step in discovering which you’re dealing with is to closely examine your ceiling and roof to spot where the leak may be coming from. To do this, you may have to clear away a bit of moisture and residue from your roof’s surface. Once you’re satisfied that you’ve recognized the source of your leaky flat roof, it’s time to select your course of action. Sometimes, a quick fix may be your best option, as it will give you time to contemplate your next steps, save for a full flat roof sub, or get quotes from professional roofers. However, if the deterioration to your flat roof is more comprehensive, the only option left to you may be an additional permanent fix such as a full flat roof replacement.

Follow the manufacturer's instructions when installing roofing material;

This may appear simple, but it's something we see on DIY projects and expansions all the time. Most manufacturers will advocate turning up the top and turning down the bottom of the sheets, which must be done using a turn up and turn down tool.

Extend the roof sheets into the gutter;

The greater the overhang into a gutter, the less probability of capillary action of water creeping back up the roof sheet and penetrating the roof. The bare minimum is 50mm. We recommend starting with 100mm of overhang on a level roof. Aim for 150mm if possible. Just remember to provide extra space for gutter maintenance.

Connect the gutter to the roof sheeting with a gutter flashing;

This flashing sits on the front edge of the lowest batten and has a squash fold to deflect any potential water flow sideways rather than back into the roof. When placing profile filler at the gutter edge, this flashing is also required.

Sheet profile fillers at the tops and bottoms;

Install a pre-formed foam filler between the roof sheet and the gutter flashing at the gutter edge of the roof. This will serve as a physical barrier against water. To prevent water infiltration into the building, install a profile filler at the highest places under a ridge cap or apron flashing.


To fix a leak or any damage on your roof, please call us at 553 Prospect Avenue Brooklyn NY 11215 (646)-838-0441 to receive superior service.

Royal Renovators Inc is Fully Licensed and Insured, with Offices Throughout the NYC Area.
Contact Us

553 Prospect Avenue, Brooklyn NY 11215

Drag a button, link, or anything else into the icon box to place it below the text. Lorem ipsum dolor sit amet elit.

Mon - Sun: 7:00AM - 9PM

Drag a button, link, or anything else into the icon box to place it below the text. Lorem ipsum dolor sit amet elit.

Copyright © 2016 All rights reserved.