AU7483787A

AU7483787A - Frame construction/loft construction and method for enlarging the floor area in a house

Info

Publication number: AU7483787A
Application number: AU74837/87A
Authority: AU
Inventors: Halfdan Langeland
Original assignee: LANGELAND H
Current assignee: LANGELAND H
Priority date: 1986-06-06
Filing date: 1987-06-05
Publication date: 1988-01-11
Also published as: EP0281571A1; DK369188D0; NO862262D0; WO1987007666A1; NO862262L

Description

Frame construction/loft construction and method for enlarging the floor area in a house

The present invention relates to a method for enlarging the living area in a dwelling house, preferably a relatively small or medium-sized single-family house/terrace house with ridge, saddle or hipped roof, where the roof trusses have a top angle which is so large that the loft cannot be lived in and which in all other respects correspond with the introductory part of the subsequent claim 1. The invention also relates to a new roof construction with new technical detail solutions for use when implementing this method.

Until now enlargement of the living area of a single- family house by building on a loft storey has been a relatively little used solution. An important contributing reason therefore has been that this entailed in part comprehensive, time-consuming and costly- work, while at the same time the encroachments on the dwelling were characterised as extensive. With this type of living space enlargement it has hitherto been necessary to dismantle the outer roof and to remove the existing trusses. The removal of the trusses has in most cases been synonymous with that the house could not be lived in during the conversion period, and in addition this contributed to the risk of water damage since for certain periods of time the building is partly open to wind and weather (without roof) and is thus exposed to the disadvantages which this entails. In connection with this known method extensive work was involved due to the conversion of the dwelling's ceiling. The solutions previously chosen substantially meant that a staregr was built on, i.e. that it was essential to erect load-bearing walls in the main storey corresponding to the load-bearing walls on the loft. It was also necessary to ensure that said supports were directly linked with the support in the foundation. In practice this frequently did not prove possible owing to different plan solutions and facility details in the three levels. The alternative for achieving a larger living area has consisted in erecting an extension to the main house; this solution has been used a lot, with varying results. The disadvantage of an extension is primarily that the costs are relatively high, mainly due to the fact that the same work has to be carried out as when erecting a one-family house, i.e. foundation work, foundation walls, main storey and roof. The costs of an extension can be compared with the costs of a single-family house_., leaving aside in either case the possibility of work by the owner himself. (The price per square metre of living area today amounts to about kr. 4_»500 plus VAT, with the costs of course varying somewhat from district to district.) A definite advantage of opting for enlargement of the living area by extension as compared with the above mentioned building-on of a loft storey suitable for living in consists in the fact that the owner can continue to live in the house and to use it while it is being converted. A similarly definite disadvantage consists in the encroachment on the site and the reduction of the site area. Furthermore enlargement of the area by extension can frequently be impossible owing to the fact that the sites in regulated building estates are frequently not sufficiently large to allow enlargement of the house by extension, and in such cases the enlargement of the living area has been inhibited.

In accordance with the present invention the general aim has been to avoid, the disadvantages and defects associated with the state of the art and thus to arrive primarily at a method involving such measures as to enable the work to be carried out very quickly and particularly efficiently, another aim being to achieve a construction of high mechanical strength and low weight. Further, closely related objects will be apparent from the following description.

With a view to achieving these and other objectives the invention is distinguished by the characteristics listed in the characterising part of the subsequent claims.

With such a method the costs are inter alia roughly half as high as the costs per square metre of living area (the calculated average price amounts to about kr. 2,500 incl. VAT per square metre of living area as in January 1986). The construction time is short since the specialised work can normally be completed within 10 hours, the entire duration of the work having been calculated as amounting to from 10 to 12 days. The method in accordance with the invention also involves a minimum encroachment on the living floor of the house,- it being sufficie to change and mount the staircase; there is no reduction or disturbance of the used site/ground area and no conflict as regards the boundaries of adjacent property. Incidentally it may be mentioned that a roof flo having an age of about 20 years must often be replaced, and the inventio can be used to advantage with all single-family houses of the type concerned which have been built during the period from about 1 60 to the present, as a result of which the costs are already a considerable amoun smaller than the costs associated with the building of an extension. It stands to reason that in the course of converting to a loft storey capable of being lived in the roof floor and underroof are removed.

Other aims, advantages and features of the invention appear from the following description of an illustrative, non-restrictive embodiment shown in the attached drawings Fig- I, II representing in vertical cross-section technical details and illustrate the method according to the invention as it is carried out.

In the drawing the reference number 10 relates to the existing trusses. The "construction pack" on which the method^' and the prefabricated roof elements for its implementation are based comprises the following steps:

1. Inspection of the actual building project with a view to ascertaini the following points: a) The length of the lower truss chords, b) the dimensions of transoms over doors and windows, c) control measurement of possible recesses in outer walls, d) examination of columns for load-bearing purposes and as foundations. It may be mentioned that all single-family houses built during the period from i960 to the present must, according to the building regulations, have sufficient bearing capacity in the outer walls for heavy roofs/loft roofs.

2. New drawings are prepared (facades, sections and plans). The probl of a staircase leading to the loft is solved by locating it above the existing basement staircase, or in the case o houses without basement, by using one of the floorson the main level as an area for the staircase. As soon as the council has granted building permission, the building work can commence. 3- Removal of existing roof floor and the gable top cladding (which can be carried out by the owner himself) . It should be noted that upright boards, roof gutters, rainwater heads and suspended roofs/ underroofs or possible shingles are normally not to be dismantled.

The new system is in principle based on this being retained and the roof being tight during the construction period, which again means a reduction in costs. 4- Once the dismantling operation has been completed, 3 joiners are put to work on the building and the new construction 2 is mounted.

The roof construction is prefabricated and dimensioned according to the calculations in such a way that laths for ventilation and cladding are not necessary (see design of rafters).

If flat attic rooms are to be installe in the loft storey, they too should be prefabricated.

As shown in the drawing the new roof construction 11 is placed next to the old construction 10 and glued and nailed to the latter. By combining the new trusses with the old ones (2) additional support is achieved, and the ceiling in the main storey is not affected by the construction work. It is noted that the subchord/beam of the new trusses is so dimensioned that with regard to the clear span between the jamb walls the layer of beams becomes self-bearing, i.e. that a support is not necessary. With extra long spans subchords/loft beams can be clamped and for further reinforcement hidden supports resting on the outer walls can be provided.

Directly after mounting the new roof construction 2 the suspended roof and laths are assembled (one gable is open) . According to the calculations it takes three men about 10 hours to assemble the trusses and to seal the new outer roof and gables.

Once this work has been done, the old roof and the trusses 1 which are within the living space of the new loft floor are removed and taken out through the open gable. Subsequently windows are fitted, the roof is covered e.g. with concrete tiles, the gable walls are fitted with laths and clad, the staircase is changed and the staircase leading to the loft is fitted.

It has been calculated that the entire reconstruction takes from 10 to 12 days.

Incidentally, hipped roofs too can be converted according to the same system, with that difference that on the gable sides the roof is closed with a half hip up to the loft gable. In this case the gable wall is pulled back 120 cm by comparison with the gable wall of the dwelling house.

Claims

1. A frame construction/loft construction is characterised in that it is a prefabricated, non-assembled frame construction, the rafters of which form a self-bearing frame construction following assembly on the construction site. 5 2. A frame construction/loft construction according to claim 1, characterised in that one provides for a separate lead-through of the subchord/beam on the frame/footpoint at the side of the existing roof truss (1) in the existing roof.

3. A frame construction/loft construction according to claims 1-2 '|0 is characterised in that a new roof truss is constructed with the aid of prefabricated non-assembled frame constructions, through and above the existing roof (i).

4- A frame construction/loft construction according to claims 1-3 is characterised in that it is secured by lateral reinforcement and in 15 that new and old constructions are fixed, to one another at all coinciding points (2).

5. A frame construction/loft construction according to claims 1-4 is characterised in that the new roof is covered before the old. construction within the loft is cut down. 20 β. A frame construction/loft construction according to claims 1-5 is characterised in that we obtain a freely suspended floor and freely suspended attic rooms which can be located as required.

7« A frame construction/loft construction according to claims 1-6 is characterised in that one retains the old head and roof gutter (3). 25 8. A frame construction/loft construction according to claims 1-7 is characterised in that a continuous capping piece/footpoint lock (4) is mounted, into which the cut-out recess in section (5) of the spar drops.

9. A frame construction/loft construction according to claims 1-8 0 is characterised in that the uprights (6) constitute a bearing point for the new layer of loft beams.

10. A frame construction/loft construction according to claims 1-9 is characterised in that two recesses are cut into the uprights for strips (7) for securing the insulation. 11. A frame construction/loft construction according to claims 1-10 is characterised in that the rafters are secured with the aid of a beam shoe (8) by way of footpoint securing device and doubly secured by means of a locking iron ( ) . 12. A method for enlarging the floor area in a house is characterised in that the frame construction is assembled on the construction site without first removing the old roof and in that one uses the existing roof as a co-support.

13. A method for enlarging the floor area ... according to claim 12 is characterised in that the outer roof is removed at its lower part, and possibly the entire roof. The underroof is retained so that the roof continues to be tight.

14« A method for enlarging the floor area ... according to claims 12-13 characterised in that a recess about 300 mm long and 70 mm wide is cut at the side of the existing roof trusses at both sides of the roof. The recesses are covered with plastic and possibly cardboard in order to prevent leaks in the lead-through.

15. A method for enlarging the floor area ... according to claims 12-14 characterised in that subchords/beams are pulled through the recesses and assembled with the existing subchords. Few subchords now project outside the old roof. Few cappings to support spars are mounted on the subchord (il).

16. A method for enlarging the floor area ... according to claims 12-15 characterised in that spars specially adapted at the footpoints and ridges and reinforced for the fixing of uprights/jamb walls are mounted.

17« A method^' for enlarging the floor area ... according to claims

12-16 characterised in that one fits a new sub-roof and new laths on the new spars before removing the old roof. The old roof can at the same time be used as staging for these operations and for mounting the spars, as a result of which no costs or extra time are required for the construction of staging.

18. A method for enlarging the floor area ... according to claims

12-17 characterised in that one can take away that part of the old roof which must be removed and in that uprights/jamb walls are mounted in the new construction. The latter are to be mounted as instructed by the manufacturer and in such a way that the junction points between the uprights and the layer of beams form support points for the new layer of loft beams. In this way one causes said layer of beams to be clamped, which is essential for dimensioning the construction, i.e. so that the layer of beams/subchord is self-bearing. The old and new ra ter constructions are secured at all coinciding points. Those parts of the old roof trusses which are located within the new loft space are cut away and removed. The last gable is relined and.the windows are fitted.

19- method for enlarging the floor area ... according to claims 12-18 characterised in that with long underchord spans iron beams or steel girders can be drawn through the subchord so as to form a hidden support. 20. A method, for enlarging the floor area ... according to claims 12-19 characterised in that a top beam/support point for laminates is fitted, the staircase is changed and a staircase mounted. A balcony is mounted at right angles to the . The top flanges of the subchords act as a bearing. The loft is now ready for furnishing.