How to insulate a metal front door

Recommendation points

• Requirements for door construction
• Fastener system design
• Where and which pad to get
• Insulation materials
• Fitting, assembly, fittings insertion
• Eliminate blowing

Heavy steel doors will become very neat and warm if you are puzzled by the manufacture of decorative plates and honeycomb insulation. Today we will talk about the refinement of a simple metal door to obtain high aesthetic qualities, insulation, elimination of condensation and freezing of ice on the door leaf..

Requirements for door construction

In an attempt to keep warm in a home, they often resort to methods that do not give a tangible effect, if not even carry negative consequences. When we talk about the insulation of the front door, we mean a fairly thin partition, to eliminate the outflow of heat through which it is almost impossible to completely. Therefore, insulation should be as effective as possible..

Let’s make a reservation right away that not every door can be insulated well. The standard door leaf construction – sheet metal and steel corner frame – is ideal for insulation. It is only important that the corners of this frame are located without spatial distortion: the edges of the shelves should lie in the same plane, without level differences of more than 1–1.5 mm. At fillet welds, especially at the bottom, technological gaps should be provided..

Particular attention should be paid to ensure that there are no additional structures inside the frame. If the intermediate bars are an attempt to improve the strength characteristics of the web, there is nothing to be done. But insulation will suffer greatly from this – steel ribs of rigidity are stable bridges of cold.

Fastener system design

Door insulation includes filler and decorative strip. With the fixing of the filler, difficulties will not arise if materials are selected that retain their shape well and with a sufficiently high density. Such an insert, sandwiched between the steel sheet and the pad, will stand intact for decades. It is more difficult to develop a high-quality system for attaching the pad to the steel structure.

Here you will need to add an inner perimeter to the frame, made up of four wooden planks 40 mm wide and 20-25 mm thick, preferably calibrated. The door leaf must be removed and placed with the wrong side up, make sure that the edges of the frame are flat, and if necessary, grind the protruding parts. Do not be lazy – carry out the restoration and apply a protective coating to the metal. Since the back surface will remain unattended, do everything according to the rules: cleaning, converter, degreasing, primer and a couple of layers of nitro enamel.

From the inside, along the contour of the corners, apply polyurethane foam with a sufficiently thick layer. Pressing a flat batten against the steel frame, sink the wooden planks into the foam so that their upper edges are flush with the canvas frame, and a layer of foam of about 2-3 mm remains between the strip and the corner. Then sink the wooden frame another 1.5-2 mm deeper, inserting chips under the rule-like.

When the foam dries, drill holes on the outside of the corner and tighten the wood to the frame with screws or bolts. For reference: in the manufacture of doors, studs are welded in advance to hide the attachment points. To insulate the area of ​​the locks, insert a sleeve from a sewer 50 mm pipe between the lock body and the canvas and fill the space with polyurethane foam. From the inside, you can cover the lock with an EPS or PUR pad. All that remains is to cut off excess foam and the door will be ready for further work..

Where and which pad to get

The best option for interior cladding of an entrance door is an MDF plate with a texture and color matched to the baseboard in the hallway. Such an overlay can be made to order in most furniture enterprises, the average price is 1-5 thousand rubles per m². It will cost a little more to apply a pattern or cover with an acrylic film.

The cover plate is made so that its edges come out flush with the framing steel corner, in other words, MDF covers the edges of the corners completely. It is desirable that the overlay has a decorative covering inside out, and the edges are smoothed with a chamfer.

Any internal siding system can be used instead of an overlay. A plastic sandwich with a polyurethane core is well suited – it, like MDF, itself is a good insulation.

In this case, you will have to place the overlay completely inside the framing frame and this is the main drawback of the method. The edges of the corners will be visible, the junction will have to be sealed, and the fastening strips will additionally be recessed by the thickness of the starting profile.

You will also need to add a few embedded crossbars for attaching the sandwich and arrange a mortgage for attaching the lock hardware. Usually, two slats 65 cm from the bottom and top of the door are sufficient, fixed flush with the wooden frame with steel corners. In doors more than a meter wide, you will need to install intermediate brackets for attaching additional frame crossbars. In the simplest case, these are ordinary short sections of the corner, welded to the canvas from the inside out. The planks are fastened to them by the same method as for a wooden frame – with self-tapping screws with pre-landing on foam.

Insulation materials

The main problem with door insulation is the formation of condensation on the door leaf. For painted steel, moisture is relatively harmless, but it can play a cruel joke with loose insulation. Usually, at least some sense of periodically soaking mineral wool is preserved only in the first 2-3 years of operation, then the filler has to be changed.

To avoid the effect of condensation, you can use polymeric materials – polyurethane foam, PIR or extruded polystyrene foam. Cheaper polystyrene is poorly suited – it tends to absorb moisture, giving a chance to mold and mildew development.

Plate insulation is very easy to use. It is glued in separate fragments onto a small amount of polyurethane foam. There can be multiple layers with any stacking order. Only two points are important:

1. Insulation should not protrude above wooden slats.
2. All voids must be carefully filled with polyurethane foam..

Mineral insulation can be used just as well, if properly prepared. Usually, two rectangular mats are cut for one door with a total size of 20–30 mm more than the internal space. Each block of insulation is wrapped in an envelope made of polyamide film, the seams are neatly tucked up and glued with adhesive tape. Inside, 2-3 sachets with silica gel should be laid out to absorb the remaining moisture that has penetrated into the cotton during packing.

Fitting, assembly, fittings insertion

To mount the cover, it must be oriented on the frame, achieving equal indents on all sides. Pressing the slab with oppression, drill a 4 mm hole in diagonally opposite corners, then make a countersink under the furniture confirmation. After fixing the strip to the wooden frame in two places, drill the remaining corners and tighten them, then remove the oppression and add fasteners around the perimeter in 40 mm increments.

Now the junction of the lining needs to be sealed, it is done this way: the confirmations are unscrewed, the MDF is removed, a foam foil cutout of the corresponding dimensions is laid inside the frame on wooden slats. Then the plate must be returned to its place and the fasteners must be screwed back.

For the manufacture of technological holes for the installation of an eyelet, a handle and decorative overlays for locks, their centers are marked from the street side with a long drill through and through. A hole is drilled under the peephole with a crown, then screw the mounting sleeve, and into it – the peephole itself.

Cutouts for locks can be made by attaching a decorative overlay on the seamy side – usually it is wide enough so that a hole can be made with a margin. The same principle works with the handle and with the pin lock larvae, but with a small caveat: the larva will still have to be temporarily pulled out, while the lever lock has a fairly wide hole in the very center.

Eliminate blowing

There remains one small touch – to eliminate the blowing of the door by sealing the vestibule. Self-adhesive sealing strips are used for it, preferably rubber and double-row. The optimal scheme of the sticker with the formation of a double vestibule is as follows:

1. The back of the web is cleaned and degreased.
2. One double-row strip is glued around the perimeter.
3. A counter strip is attached to it on small balls of plasticine in such a way that one of the sides is oriented just between two opposite.

After the false surfaces of the door frame are also cleaned and degreased, protective films are removed from the adhesive surface. The door now needs to be gently closed and pressed, while the opposite strips will stick firmly, and the plasticine balls will easily fall behind.